The surgical removal of one or both ovaries.
Surgical removal or artificial destruction of gonads.
The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids.
Compounds that interact with ESTROGEN RECEPTORS in target tissues to bring about the effects similar to those of ESTRADIOL. Estrogens stimulate the female reproductive organs, and the development of secondary female SEX CHARACTERISTICS. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds.
The reproductive organ (GONADS) in female animals. In vertebrates, the ovary contains two functional parts: the OVARIAN FOLLICLE for the production of female germ cells (OOGENESIS); and the endocrine cells (GRANULOSA CELLS; THECA CELLS; and LUTEAL CELLS) for the production of ESTROGENS and PROGESTERONE.
The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.
The hollow thick-walled muscular organ in the female PELVIS. It consists of the fundus (the body) which is the site of EMBRYO IMPLANTATION and FETAL DEVELOPMENT. Beyond the isthmus at the perineal end of fundus, is CERVIX UTERI (the neck) opening into VAGINA. Beyond the isthmi at the upper abdominal end of fundus, are the FALLOPIAN TUBES.
The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.
A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity.
A phase of the ESTROUS CYCLES that follows METESTRUS. Diestrus is a period of sexual quiescence separating phases of ESTRUS in polyestrous animals.
A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Follicle-stimulating hormone stimulates GAMETOGENESIS and the supporting cells such as the ovarian GRANULOSA CELLS, the testicular SERTOLI CELLS, and LEYDIG CELLS. FSH consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity.
Reduction of bone mass without alteration in the composition of bone, leading to fractures. Primary osteoporosis can be of two major types: postmenopausal osteoporosis (OSTEOPOROSIS, POSTMENOPAUSAL) and age-related or senile osteoporosis.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
The measurement of an organ in volume, mass, or heaviness.
Achievement of full sexual capacity in animals and in humans.
The use of hormonal agents with estrogen-like activity in postmenopausal or other estrogen-deficient women to alleviate effects of hormone deficiency, such as vasomotor symptoms, DYSPAREUNIA, and progressive development of OSTEOPOROSIS. This may also include the use of progestational agents in combination therapy.
The longest and largest bone of the skeleton, it is situated between the hip and the knee.
The process of bearing developing young (EMBRYOS or FETUSES) in utero in non-human mammals, beginning from FERTILIZATION to BIRTH.
The period of cyclic physiological and behavior changes in non-primate female mammals that exhibit ESTRUS. The estrous cycle generally consists of 4 or 5 distinct periods corresponding to the endocrine status (PROESTRUS; ESTRUS; METESTRUS; DIESTRUS; and ANESTRUS).
Steroid hormones produced by the GONADS. They stimulate reproductive organs, germ cell maturation, and the secondary sex characteristics in the males and the females. The major sex steroid hormones include ESTRADIOL; PROGESTERONE; and TESTOSTERONE.
The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.
A phase of the ESTROUS CYCLE that precedes ESTRUS. During proestrus, the Graafian follicles undergo maturation.
Bone loss due to osteoclastic activity.
Experimentally induced mammary neoplasms in animals to provide a model for studying human BREAST NEOPLASMS.
The discharge of an OVUM from a rupturing follicle in the OVARY.
A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.
The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.
The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.
A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.
Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.
A state of sexual inactivity in female animals exhibiting no ESTROUS CYCLE. Causes of anestrus include pregnancy, presence of offspring, season, stress, and pathology.
A small, unpaired gland situated in the SELLA TURCICA. It is connected to the HYPOTHALAMUS by a short stalk which is called the INFUNDIBULUM.
Metabolic bone diseases are a group of disorders that affect the bones' structure and strength, caused by disturbances in the normal metabolic processes involved in bone formation, resorption, or mineralization, including conditions like osteoporosis, osteomalacia, Paget's disease, and renal osteodystrophy.
An antipsychotic phenothiazine derivative with actions and uses similar to those of CHLORPROMAZINE.
A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.
The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.
Small containers or pellets of a solid drug implanted in the body to achieve sustained release of the drug.
One of the ESTROGEN RECEPTORS that has marked affinity for ESTRADIOL. Its expression and function differs from, and in some ways opposes, ESTROGEN RECEPTOR BETA.
The surgical removal of one or both testicles.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
An OOCYTE-containing structure in the cortex of the OVARY. The oocyte is enclosed by a layer of GRANULOSA CELLS providing a nourishing microenvironment (FOLLICULAR FLUID). The number and size of follicles vary depending on the age and reproductive state of the female. The growing follicles are divided into five stages: primary, secondary, tertiary, Graafian, and atretic. Follicular growth and steroidogenesis depend on the presence of GONADOTROPINS.
The period following ESTRUS during which the phenomena of estrus subside in those animals in which pregnancy or pseudopregnancy does not occur.
One of the ESTROGEN RECEPTORS that has greater affinity for ISOFLAVONES than ESTROGEN RECEPTOR ALPHA does. There is great sequence homology with ER alpha in the DNA-binding domain but not in the ligand binding and hinge domains.
A nitrosourea compound with alkylating, carcinogenic, and mutagenic properties.
Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.
Pregnenes with one double bond or more than three double bonds which have undergone ring contractions or are lacking carbon-18 or carbon-19..
A hollow part of the alveolar process of the MAXILLA or MANDIBLE where each tooth fits and is attached via the periodontal ligament.
X-RAY COMPUTERIZED TOMOGRAPHY with resolution in the micrometer range.
A decapeptide that stimulates the synthesis and secretion of both pituitary gonadotropins, LUTEINIZING HORMONE and FOLLICLE STIMULATING HORMONE. GnRH is produced by neurons in the septum PREOPTIC AREA of the HYPOTHALAMUS and released into the pituitary portal blood, leading to stimulation of GONADOTROPHS in the ANTERIOR PITUITARY GLAND.
Cytoplasmic proteins that bind estrogens and migrate to the nucleus where they regulate DNA transcription. Evaluation of the state of estrogen receptors in breast cancer patients has become clinically important.
A second generation selective estrogen receptor modulator (SERM) used to prevent osteoporosis in postmenopausal women. It has estrogen agonist effects on bone and cholesterol metabolism but behaves as a complete estrogen antagonist on mammary gland and uterine tissue.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
Compounds which inhibit or antagonize the action or biosynthesis of estrogenic compounds.
Elements of limited time intervals, contributing to particular results or situations.
The continuous turnover of BONE MATRIX and mineral that involves first an increase in BONE RESORPTION (osteoclastic activity) and later, reactive BONE FORMATION (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium HOMEOSTASIS. An imbalance in the regulation of bone remodeling's two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as OSTEOPOROSIS.
7,12-Dimethylbenzanthracene. Polycyclic aromatic hydrocarbon found in tobacco smoke that is a potent carcinogen.
Collection of granular epithelial cells in the uterine muscle beneath the placenta that develop during pregnancy in certain species of animals.
Hormones secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR) that stimulate gonadal functions in both males and females. They include FOLLICLE STIMULATING HORMONE that stimulates germ cell maturation (OOGENESIS; SPERMATOGENESIS), and LUTEINIZING HORMONE that stimulates the production of sex steroids (ESTROGENS; PROGESTERONE; ANDROGENS).
A nonhormonal medication for the treatment of postmenopausal osteoporosis in women. This drug builds healthy bone, restoring some of the bone loss as a result of osteoporosis.
An acyclic state that resembles PREGNANCY in that there is no ovarian cycle, ESTROUS CYCLE, or MENSTRUAL CYCLE. Unlike pregnancy, there is no EMBRYO IMPLANTATION. Pseudopregnancy can be experimentally induced to form DECIDUOMA in the UTERUS.
Abnormal distention of the STOMACH due to accumulation of gastric contents that may reach 10 to 15 liters. Gastric dilatation may be the result of GASTRIC OUTLET OBSTRUCTION; ILEUS; GASTROPARESIS; or denervation.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
MAMMARY GLANDS in the non-human MAMMALS.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
PLANT EXTRACTS and compounds, primarily ISOFLAVONES, that mimic or modulate endogenous estrogens, usually by binding to ESTROGEN RECEPTORS.
Delay in the attachment and implantation of BLASTOCYST to the uterine ENDOMETRIUM. The blastocyst remains unattached beyond the normal duration thus delaying embryonic development.
(6 alpha)-17-Hydroxy-6-methylpregn-4-ene-3,20-dione. A synthetic progestational hormone used in veterinary practice as an estrus regulator.
A bridged-ring tetracyclic antidepressant that is both mechanistically and functionally similar to the tricyclic antidepressants, including side effects associated with its use.
Glycoproteins that inhibit pituitary FOLLICLE STIMULATING HORMONE secretion. Inhibins are secreted by the Sertoli cells of the testes, the granulosa cells of the ovarian follicles, the placenta, and other tissues. Inhibins and ACTIVINS are modulators of FOLLICLE STIMULATING HORMONE secretions; both groups belong to the TGF-beta superfamily, as the TRANSFORMING GROWTH FACTOR BETA. Inhibins consist of a disulfide-linked heterodimer with a unique alpha linked to either a beta A or a beta B subunit to form inhibin A or inhibin B, respectively
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
A large multinuclear cell associated with the BONE RESORPTION. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in CEMENTUM resorption.
A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.
A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.
Transport of the OVUM or fertilized ovum (ZYGOTE) from the mammalian oviduct (FALLOPIAN TUBES) to the site of EMBRYO IMPLANTATION in the UTERUS.
A sebaceous gland that, in some animals, acts as an accessory to the lacrimal gland. The harderian gland excretes fluid that facilitates movement of the third eyelid.
Agents that inhibit BONE RESORPTION and/or favor BONE MINERALIZATION and BONE REGENERATION. They are used to heal BONE FRACTURES and to treat METABOLIC BONE DISEASES such as OSTEOPOROSIS.
The genital canal in the female, extending from the UTERUS to the VULVA. (Stedman, 25th ed)
In horses, cattle, and other quadrupeds, the joint between the femur and the tibia, corresponding to the human knee.
Peptides, natural or synthetic, that stimulate the release of PITUITARY HORMONES. They were first isolated from the extracts of the HYPOTHALAMUS; MEDIAN EMINENCE; PITUITARY STALK; and NEUROHYPOPHYSIS. In addition, some hypophysiotropic hormones control pituitary cell differentiation, cell proliferation, and hormone synthesis. Some can act on more than one pituitary hormone.
A plant genus of the family VITACEAE. Cissus rufescence gum is considered comparable to TRAGACANTH.
The yellow body derived from the ruptured OVARIAN FOLLICLE after OVULATION. The process of corpus luteum formation, LUTEINIZATION, is regulated by LUTEINIZING HORMONE.
Metabolic disorder associated with fractures of the femoral neck, vertebrae, and distal forearm. It occurs commonly in women within 15-20 years after menopause, and is caused by factors associated with menopause including estrogen deficiency.
Excision of one or both adrenal glands. (From Dorland, 28th ed)
The amount of a substance secreted by cells or by a specific organ or organism over a given period of time; usually applies to those substances which are formed by glandular tissues and are released by them into biological fluids, e.g., secretory rate of corticosteroids by the adrenal cortex, secretory rate of gastric acid by the gastric mucosa.
An order of small mammals comprising two families, Ochotonidae (pikas) and Leporidae (RABBITS and HARES). Head and body length ranges from about 125 mm to 750 mm. Hares and rabbits have a short tail, and the pikas lack a tail. Rabbits are born furless and with both eyes and ears closed. HARES are born fully haired with eyes and ears open. All are vegetarians. (From Nowak, Walker's Mammals of the World, 5th ed, p539-41)
Twisting of the STOMACH that may result in gastric ISCHEMIA and GASTRIC OUTLET OBSTRUCTION. It is often associated with DIAPHRAGMATIC HERNIA.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
The process of bone formation. Histogenesis of bone including ossification.
A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.

Relaxin is a potent renal vasodilator in conscious rats. (1/4238)

The kidneys and other nonreproductive organs vasodilate during early gestation; however, the "pregnancy hormones" responsible for the profound vasodilation of the renal circulation during pregnancy are unknown. We hypothesized that the ovarian hormone relaxin (RLX) contributes. Therefore, we tested whether the administration of RLX elicits renal vasodilation and hyperfiltration in conscious adult, intact female rats. After several days of treatment with either purified porcine RLX or recombinant human RLX 2 (rhRLX), effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) increased by 20%-40%. Comparable renal vasodilation and hyperfiltration was also observed in ovariectomized rats, suggesting that estrogen and progesterone are unnecessary for the renal response to rhRLX. The nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester completely abrogated the increase in ERPF and GFR elicited by chronic administration of purified porcine RLX. In contrast, the renal vasoconstrictory response to angiotensin II was attenuated by the RLX treatment. Short-term infusion of purified porcine RLX to conscious rats over several hours failed to increase ERPF and GFR. Plasma osmolality was consistently reduced by the chronic administration of both RLX preparations. In conclusion, the renal and osmoregulatory effects of chronic RLX administration to conscious rats resemble the physiological changes of pregnancy in several respects: (a) marked increases in ERPF and GFR with a mediatory role for nitric oxide; (b) attenuation of the renal circulatory response to angiotensin II; and (c) reduction in plasma osmolality.  (+info)

Steroid regulation of retinol-binding protein in the ovine oviduct. (2/4238)

Two studies were conducted to identify retinol-binding protein (RBP) expression in the ovine oviduct and to determine the role of ovarian steroids in its regulation. Ewes were salpingectomized on Days 1, 5, or 10 of their respective estrous cycles, and oviducts were homogenized for RNA analysis, fixed for immunocytochemistry (ICC), or cultured for 24 h for protein analysis. ICC localized RBP to the epithelium of all oviducts. RBP synthesis was demonstrated by immunoprecipitation of radiolabeled RBP from the medium of oviductal explant cultures. Explant culture medium from oviducts harvested on Day 1 contained significantly more RBP than medium from oviducts collected on Days 5 or 10. Slot-blot analysis demonstrated that steady-state RBP mRNA levels were significantly higher on Day 1 than Day 5 or 10. In the second experiment, ovariectomized ewes were treated with estradiol-17beta (E2), progesterone (P4), E2+P4 (E2+P4), or vehicle control, and oviducts were analyzed as above. P4 alone or in combination with E2 significantly reduced steady-state RBP mRNA levels compared to those in E2-treated animals. Oviductal explants from E2- and E2+P4-treated animals released 3- to 5-fold more RBP into the medium than control and P4 treatments as determined by ELISA. RBP synthesis of metabolically labeled RBP was increased by E2 and E2+P4 treatments. This study demonstrates that P4 applied on an estradiol background negatively regulates RBP gene expression in the oviduct whereas estradiol appears to stimulate RBP synthesis and secretion.  (+info)

Effect of shellfish calcium on the apparent absorption of calcium and bone metabolism in ovariectomized rats. (3/4238)

Fossil shellfish powder (FS) and Ezo giant scallop shell powder (EG) were rendered soluble with lactate and citrate under decompression (FSEx and EGEx, respectively) and we examined the effects of lactate-citrate solubilization of FS and EG on mineral absorption, tissue mineral contents, serum biochemical indices and bone mineral density (BMD) in ovariectomized (OVX) rats. The apparent absorption ratios of minerals tended to be high in the rats fed with the solubilized mineral sources, those in the FSEx group being significantly higher than in the FS group. There was no significant difference in the tibia mineral content among the OVX groups. BMD at the distal femoral diaphysis was significantly increased by FSEx and EGEx feeding. It is suggested that solubilization with lactate and citrate under decompression increased the solubility and bioavailability of calcium from such natural sources of shellfish calcium as FS and EG.  (+info)

Expression of calcium binding protein D-9k messenger RNA in the mouse uterine endometrium during implantation. (4/4238)

To investigate the molecular mechanisms of implantation, we constructed a cDNA library of mouse uteri enriched with pregnancy-induced genes by subtractive hybridization and polymerase chain reaction (PCR). One of the isolated clones was the cDNA for the calcium binding protein D-9k (Cabp9k), which is considered to regulate intracytoplasmic concentration and transport of free calcium ions. Northern blot and in-situ hybridization analyses demonstrated that the Cabp9k mRNA was expressed in the endometrial epithelia, both luminal and glandular, in the uterus at the time of implantation. On pregnancy day 5 it was detected in the luminal, but not in the glandular, epithelia. In the oophorectomized adult mice, progesterone enhanced Cabp9k mRNA expression in the uterus, whereas oestrogen did not. Consistent with this, a nucleotide change was identified in the first intron of mouse Cabp9k gene corresponding to the oestrogen responsive element in the rat Cabp9k gene. Transfer of embryos into the uterine cavity of pseudopregnant mice reduced the expression of Cabp9k mRNA in the glandular epithelium, suggesting that Cabp9k mRNA expression is also regulated by embryonal signal(s). These findings demonstrated that Cabp9k mRNA is expressed in the endometrial epithelia during the implantation period under the control of progesterone and the presence of embryo, and suggest that CaBP9k plays a role in implantation by regulating the local calcium concentrations.  (+info)

Estrogen provides neuroprotection in transient forebrain ischemia through perfusion-independent mechanisms in rats. (5/4238)

BACKGROUND AND PURPOSE: Estrogen-related neuroprotection in association with animal models of transient forebrain and focal ischemia has been documented in several recent reports. Some of those studies indicated that part of that benefit was a function of improved intraischemic vasodilating capacity. In the present study we examined whether chronic estrogen depletion and repletion affected ischemic neuropathology through perfusion-independent mechanisms. METHODS: Normal, ovariectomized (OVX), and OVX female rats treated with 17beta-estradiol (E2) were subjected to 30 minutes of transient forebrain ischemia (right common carotid occlusion plus hemorrhagic hypotension) and reperfusion. Neurological function and brain histopathology were assessed over the 72-hour recovery period. In all rats, preischemic and intraischemic cortical cerebral blood flow (CBF) levels were monitored with laser-Doppler flowmetry. In additional rats, CBF changes in the striatum and hippocampus were also monitored with laser-Doppler flowmetry probes and radiolabeled microspheres. In each experiment, the level of ischemia was targeted to a 75% to 80% reduction in cortical CBF. RESULTS: The similarity in ischemic severity among groups was supported by measurements of comparable patterns of electroencephalographic power changes during the ischemic period. Compared with normal females, OVX rats showed diminished neurological outcomes and more severe histopathology in the hippocampus and striatum. Two-week treatment of OVX rats with E2 was accompanied by postischemic neuropathological changes similar to those seen in normal females. Intraischemic CBF reductions in the hippocampus and striatum were similar in all groups (to 35% to 50% of the preischemic value) but significantly less than the cortical CBF reductions. CONCLUSIONS: These findings indicate that estrogen provides ischemic neuroprotection through mechanisms unrelated to improvement of intraischemic cerebral perfusion.  (+info)

Androgen influence on lacrimal gland apoptosis, necrosis, and lymphocytic infiltration. (6/4238)

PURPOSE: Previous studies have shown that ovariectomy and hypophysectomy cause regression of the lacrimal gland and have implicated androgens as trophic hormones that support the gland. The purposes of this study were to test the hypothesis that glandular regression after ovariectomy is due to apoptosis, to identify the cell type or types that undergo apoptosis, to survey the time course of the apoptosis, and to determine whether ovariectomy-induced apoptosis could be prevented by dihydrotestosterone (DHT) treatment. METHODS: Groups of sexually mature female New Zealand White rabbits were ovariectomized and killed at various time periods up to 9 days. Additional groups of ovariectomized rabbits were treated with 4 mg/kg DHT per day. At each time period, sham-operated rabbits were used as controls. Lacrimal glands were removed and processed for analysis of apoptosis as assessed by DNA fragmentation and for morphologic examination. DNA fragmentation was determined using the TdT-dUTP terminal nick-end labeling assay and by agarose gel electrophoresis. Labeled nuclei were quantified by automated densitometry. Sections were also stained for RTLA (rabbit thymic lymphocyte antigen), rabbit CD18, and La antigen. Morphology was evaluated by both light and electron microscopy. RESULTS: The time course of apoptosis exhibited two phases, a rapid and transient phase and a second prolonged phase. A transient phase peaked at approximately 4 to 6 hours after ovariectomy. The values for degraded DNA as a percentage of total nuclear area were 4.29%+/-0.79% and 4.26%+/-0.54%, respectively. The values for sham-operated controls examined at the same time periods were 1.77%+/-0.08% and 0.82%+/-0.21%, respectively. The percentage of degraded DNA at 24 hours after ovariectomy was not different from controls examined at the same interval after sham operation. The percentage of degraded DNA 6 days after ovariectomy was significantly increased (8.5%+/-2.4%), compared with sham-operated animals at the same time period (0.68%+/-0.03%). DNA laddering was more pronounced after ovariectomy. Dihydrotestosterone treatment in ovariectomized rabbits suppressed the increase in DNA degradation. Morphologic examination of lacrimal gland sections indicated that ovariectomy caused apoptosis of interstitial cells rather than acinar or ductal epithelial cells. Tissue taken 4 hours and 6 days after ovariectomy showed nuclear chromatin condensation principally in plasma cells. Increased numbers of macrophages were also evident. Significant levels of cell degeneration and cell debris, characteristic of necrosis, were observed in acinar regions 6 days after ovariectomy. Dihydrotestosterone prevented this necrosis. Increased numbers of RTLA+, CD18+, and La+ interstitial cells were also evident 6 days after ovariectomy. In addition, ovariectomy increased La expression in ductal cells. Dihydrotestosterone treatment prevented the increase in numbers of lymphoid cells and La expression. Dihydrotestosterone also promoted the appearance of mitotic figures in acinar cells and increased the sizes of acini by 43% (P < 0.05). CONCLUSIONS: Glandular atrophy observed after ovariectomy is likely to proceed by necrosis of acinar cells rather than apoptosis. This process begins with an apparent time lag after a rapid phase of interstitial cell apoptosis. These processes are accompanied by increased lymphocytic infiltration. These results suggest that a critical level of androgen is necessary to maintain lacrimal gland structure and function and that a decrease in available androgen below this level could trigger lacrimal gland apoptosis and necrosis, and an autoimmune response. Because apoptotic and necrotic cell fragments may be sources of autoantigens that can be processed and presented to initiate an autoimmune reaction, we surmise that cell death triggered by androgen withdrawal may trigger an autoimmune response such as that encountered in Sjogren's syndrome. (ABSTRACT TRUNCATED)  (+info)

Effect of long-term food restriction on pituitary sensitivity to cLHRH-I in broiler breeder females. (7/4238)

The effect of long-term food restriction on the sensitivity of the pituitary to exogenously administered chicken luteinizing hormone releasing hormone I (cLHRH-I) was investigated in three groups of broiler breeder females fed ad libitum, fed a restricted quantity of food or fed a restricted quantity of food to obtain an intermediate body weight between those of the first two groups. At 16 weeks of age, basal FSH release was higher in ad libitum fed birds, culminating in ovarian development and subsequent oestradiol production by the small follicles. At this age, LH secretion was independent of ovarian feedback factors. In all groups, cLHRH-I was most active in releasing LH in intact and ovariectomized animals and, to a lesser extent, in releasing FSH in ovariectomized birds. At 39 weeks of age, basal FSH concentrations were similar among intact animals of all groups, whereas LH concentrations differed among groups, with higher values in the restricted birds. This food effect was enhanced in ovariectomized birds. Furthermore, the high response to cLHRH-I in the ovariectomized, restricted birds compared with the ad libitum, ovariectomized group suggests an improved sensitivity of the hypothalamic-pituitary axis. In conclusion, birds fed ad libitum showed the highest responsiveness to ovarian factors and to cLHRH-I in releasing FSH in the period before sexual maturity. No effect of amount of feeding could be observed for LH. However, during the egg laying period, LH release by cLHRH-I was highly dependent on amount of feeding and on ovarian feedback regulation. This finding indicates that the amount of feeding can modify the sensitivity of the pituitary to cLHRH-I, and possibly to gonadal hormones, during the laying period.  (+info)

Suppression of the secretion of luteinizing hormone due to isolation/restraint stress in gonadectomised rams and ewes is influenced by sex steroids. (8/4238)

In this study we used an isolation/restraint stress to test the hypothesis that stress will affect the secretion of LH differently in gonadectomised rams and ewes treated with different combinations of sex steroids. Romney Marsh sheep were gonadectomised two weeks prior to these experiments. In the first experiment male and female sheep were treated with vehicle or different sex steroids for 7 days prior to the application of the isolation/restraint stress. Male sheep received either i.m. oil (control rams) or 6 mg testosterone propionate injections every 12 h. Female sheep were given empty s.c. implants (control ewes), or 2x1 cm s.c. implants containing oestradiol, or an intravaginal controlled internal drug release device containing 0.3 g progesterone, or the combination of oestradiol and progesterone. There were four animals in each group. On the day of application of the isolation/restraint stress, blood samples were collected every 10 min for 16 h for the subsequent measurement of plasma LH and cortisol concentrations. After 8 h the stress was applied for 4 h. Two weeks later, blood samples were collected for a further 16 h from the control rams and ewes, but on this day no stress was imposed. In the second experiment, separate control gonadectomised rams and ewes (n=4/group) were studied for 7 h on 3 consecutive days, when separate treatments were applied. On day 1, the animals received no treatment; on day 2, isolation/restraint stress was applied after 3 h; and on day 3, an i. v. injection of 2 microg/kg ACTH1-24 was given after 3 h. On each day, blood samples were collected every 10 min and the LH response to the i.v. injection of 500 ng GnRH administered after 5 h of sampling was measured. In Experiment 1, the secretion of LH was suppressed during isolation/restraint in all groups but the parameters of LH secretion (LH pulse frequency and amplitude) that were affected varied between groups. In control rams, LH pulse amplitude, and not frequency, was decreased during isolation/restraint whereas in rams treated with testosterone propionate the stressor reduced pulse frequency and not amplitude. In control ewes, isolation/restraint decreased LH pulse frequency but not amplitude. Isolation/restraint reduced both LH pulse frequency and amplitude in ewes treated with oestradiol, LH pulse frequency in ewes treated with progesterone and only LH pulse amplitude in ewes treated with both oestradiol and progesterone. There was no change in LH secretion during the day of no stress. Plasma concentrations of cortisol were higher during isolation/restraint than on the day of no stress. On the day of isolation/restraint maximal concentrations of cortisol were observed during the application of the stressor but there were no differences between groups in the magnitude of this response. In Experiment 2, isolation/restraint reduced the LH response to GnRH in rams but not ewes and ACTH reduced the LH response to GnRH both in rams and ewes. Our results show that the mechanism(s) by which isolation/restraint stress suppresses LH secretion in sheep is influenced by sex steroids. The predominance of particular sex steroids in the circulation may affect the extent to which stress inhibits the secretion of GnRH from the hypothalamus and/or the responsiveness of the pituitary gland to the actions of GnRH. There are also differences between the sexes in the effects of stress on LH secretion that are independent of the sex steroids.  (+info)

Ovariectomy is a surgical procedure in which one or both ovaries are removed. It is also known as "ovary removal" or "oophorectomy." This procedure is often performed as a treatment for various medical conditions, including ovarian cancer, endometriosis, uterine fibroids, and pelvic pain. Ovariectomy can also be part of a larger surgical procedure called an hysterectomy, in which the uterus is also removed.

In some cases, an ovariectomy may be performed as a preventative measure for individuals at high risk of developing ovarian cancer. This is known as a prophylactic ovariectomy. After an ovariectomy, a person will no longer have menstrual periods and will be unable to become pregnant naturally. Hormone replacement therapy may be recommended in some cases to help manage symptoms associated with the loss of hormones produced by the ovaries.

Castration is a surgical procedure to remove the testicles in males or ovaries in females. In males, it is also known as orchiectomy. This procedure results in the inability to produce sex hormones and gametes (sperm in men and eggs in women), and can be done for various reasons such as medical treatment for certain types of cancer, to reduce sexual urges in individuals with criminal tendencies, or as a form of birth control in animals.

Estradiol is a type of estrogen, which is a female sex hormone. It is the most potent and dominant form of estrogen in humans. Estradiol plays a crucial role in the development and maintenance of secondary sexual characteristics in women, such as breast development and regulation of the menstrual cycle. It also helps maintain bone density, protect the lining of the uterus, and is involved in cognition and mood regulation.

Estradiol is produced primarily by the ovaries, but it can also be synthesized in smaller amounts by the adrenal glands and fat cells. In men, estradiol is produced from testosterone through a process called aromatization. Abnormal levels of estradiol can contribute to various health issues, such as hormonal imbalances, infertility, osteoporosis, and certain types of cancer.

Estrogens are a group of steroid hormones that are primarily responsible for the development and regulation of female sexual characteristics and reproductive functions. They are also present in lower levels in males. The main estrogen hormone is estradiol, which plays a key role in promoting the growth and development of the female reproductive system, including the uterus, fallopian tubes, and breasts. Estrogens also help regulate the menstrual cycle, maintain bone density, and have important effects on the cardiovascular system, skin, hair, and cognitive function.

Estrogens are produced primarily by the ovaries in women, but they can also be produced in smaller amounts by the adrenal glands and fat cells. In men, estrogens are produced from the conversion of testosterone, the primary male sex hormone, through a process called aromatization.

Estrogen levels vary throughout a woman's life, with higher levels during reproductive years and lower levels after menopause. Estrogen therapy is sometimes used to treat symptoms of menopause, such as hot flashes and vaginal dryness, or to prevent osteoporosis in postmenopausal women. However, estrogen therapy also carries risks, including an increased risk of certain cancers, blood clots, and stroke, so it is typically recommended only for women who have a high risk of these conditions.

An ovary is a part of the female reproductive system in which ova or eggs are produced through the process of oogenesis. They are a pair of solid, almond-shaped structures located one on each side of the uterus within the pelvic cavity. Each ovary measures about 3 to 5 centimeters in length and weighs around 14 grams.

The ovaries have two main functions: endocrine (hormonal) function and reproductive function. They produce and release eggs (ovulation) responsible for potential fertilization and development of an embryo/fetus during pregnancy. Additionally, they are essential in the production of female sex hormones, primarily estrogen and progesterone, which regulate menstrual cycles, sexual development, and reproduction.

During each menstrual cycle, a mature egg is released from one of the ovaries into the fallopian tube, where it may be fertilized by sperm. If not fertilized, the egg, along with the uterine lining, will be shed, leading to menstruation.

Progesterone is a steroid hormone that is primarily produced in the ovaries during the menstrual cycle and in pregnancy. It plays an essential role in preparing the uterus for implantation of a fertilized egg and maintaining the early stages of pregnancy. Progesterone works to thicken the lining of the uterus, creating a nurturing environment for the developing embryo.

During the menstrual cycle, progesterone is produced by the corpus luteum, a temporary structure formed in the ovary after an egg has been released from a follicle during ovulation. If pregnancy does not occur, the levels of progesterone will decrease, leading to the shedding of the uterine lining and menstruation.

In addition to its reproductive functions, progesterone also has various other effects on the body, such as helping to regulate the immune system, supporting bone health, and potentially influencing mood and cognition. Progesterone can be administered medically in the form of oral pills, intramuscular injections, or vaginal suppositories for various purposes, including hormone replacement therapy, contraception, and managing certain gynecological conditions.

The uterus, also known as the womb, is a hollow, muscular organ located in the female pelvic cavity, between the bladder and the rectum. It has a thick, middle layer called the myometrium, which is composed of smooth muscle tissue, and an inner lining called the endometrium, which provides a nurturing environment for the fertilized egg to develop into a fetus during pregnancy.

The uterus is where the baby grows and develops until it is ready for birth through the cervix, which is the lower, narrow part of the uterus that opens into the vagina. The uterus plays a critical role in the menstrual cycle as well, by shedding its lining each month if pregnancy does not occur.

Estrus is a term used in veterinary medicine to describe the physiological and behavioral state of female mammals that are ready to mate and conceive. It refers to the period of time when the female's reproductive system is most receptive to fertilization.

During estrus, the female's ovaries release one or more mature eggs (ovulation) into the fallopian tubes, where they can be fertilized by sperm from a male. This phase of the estrous cycle is often accompanied by changes in behavior and physical appearance, such as increased vocalization, restlessness, and swelling of the genital area.

The duration and frequency of estrus vary widely among different species of mammals. In some animals, such as dogs and cats, estrus occurs regularly at intervals of several weeks or months, while in others, such as cows and mares, it may only occur once or twice a year.

It's important to note that the term "estrus" is not used to describe human reproductive physiology. In humans, the equivalent phase of the menstrual cycle is called ovulation.

Luteinizing Hormone (LH) is a glycoprotein hormone, which is primarily produced and released by the anterior pituitary gland. In women, a surge of LH triggers ovulation, the release of an egg from the ovaries during the menstrual cycle. During pregnancy, LH stimulates the corpus luteum to produce progesterone. In men, LH stimulates the testes to produce testosterone. It plays a crucial role in sexual development, reproduction, and maintaining the reproductive system.

Diestrus is a stage in the estrous cycle of animals, which is similar to the menstrual cycle in humans. It follows the phase of estrus (or heat), during which the animal is receptive to mating. Diestrus is the period of relative sexual quiescence and hormonal stability between cycles. In this phase, the corpus luteum in the ovary produces progesterone, preparing the uterus for potential pregnancy. If fertilization does not occur, the corpus luteum will degenerate, leading to a drop in progesterone levels and the onset of the next estrous cycle. The duration of diestrus varies among species.

In humans, this phase is analogous to the luteal phase of the menstrual cycle. However, since humans do not exhibit estrous behavior, the term 'diestrus' is typically not used in human reproductive physiology discussions.

Follicle-Stimulating Hormone (FSH) is a glycoprotein hormone secreted and released by the anterior pituitary gland. In females, it promotes the growth and development of ovarian follicles in the ovary, which ultimately leads to the maturation and release of an egg (ovulation). In males, FSH stimulates the testes to produce sperm. It works in conjunction with luteinizing hormone (LH) to regulate reproductive processes. The secretion of FSH is controlled by the hypothalamic-pituitary-gonadal axis and its release is influenced by the levels of gonadotropin-releasing hormone (GnRH), estrogen, inhibin, and androgens.

Osteoporosis is a systemic skeletal disease characterized by low bone mass, deterioration of bone tissue, and disruption of bone architecture, leading to increased risk of fractures, particularly in the spine, wrist, and hip. It mainly affects older people, especially postmenopausal women, due to hormonal changes that reduce bone density. Osteoporosis can also be caused by certain medications, medical conditions, or lifestyle factors such as smoking, alcohol abuse, and a lack of calcium and vitamin D in the diet. The diagnosis is often made using bone mineral density testing, and treatment may include medication to slow bone loss, promote bone formation, and prevent fractures.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

Organ size refers to the volume or physical measurement of an organ in the body of an individual. It can be described in terms of length, width, and height or by using specialized techniques such as imaging studies (like CT scans or MRIs) to determine the volume. The size of an organ can vary depending on factors such as age, sex, body size, and overall health status. Changes in organ size may indicate various medical conditions, including growths, inflammation, or atrophy.

Sexual maturation is the process of physical development during puberty that leads to the ability to reproduce. This process involves the development of primary and secondary sexual characteristics, changes in hormone levels, and the acquisition of reproductive capabilities. In females, this includes the onset of menstruation and the development of breasts and hips. In males, this includes the deepening of the voice, growth of facial hair, and the production of sperm. Achieving sexual maturation is an important milestone in human development and typically occurs during adolescence.

Estrogen Replacement Therapy (ERT) is a medical treatment in which estrogen hormones are administered to replace the estrogen that is naturally produced by the ovaries but declines, especially during menopause. This therapy is often used to help manage symptoms of menopause such as hot flashes, night sweats, and vaginal dryness. It can also help prevent bone loss in postmenopausal women. ERT typically involves the use of estrogen alone, but in some cases, a combination of estrogen and progestin may be prescribed for women with a uterus to reduce the risk of endometrial cancer. However, ERT is associated with certain risks, including an increased risk of breast cancer, blood clots, and stroke, so it's important for women to discuss the potential benefits and risks with their healthcare provider before starting this therapy.

The femur is the medical term for the thigh bone, which is the longest and strongest bone in the human body. It connects the hip bone to the knee joint and plays a crucial role in supporting the weight of the body and allowing movement during activities such as walking, running, and jumping. The femur is composed of a rounded head, a long shaft, and two condyles at the lower end that articulate with the tibia and patella to form the knee joint.

"Animal pregnancy" is not a term that is typically used in medical definitions. However, in biological terms, animal pregnancy refers to the condition where a fertilized egg (or eggs) implants and develops inside the reproductive tract of a female animal, leading to the birth of offspring (live young).

The specific details of animal pregnancy can vary widely between different species, with some animals exhibiting phenomena such as placental development, gestation periods, and hormonal changes that are similar to human pregnancy, while others may have very different reproductive strategies.

It's worth noting that the study of animal pregnancy and reproduction is an important area of biological research, as it can provide insights into fundamental mechanisms of embryonic development, genetics, and evolution.

The estrous cycle is the reproductive cycle in certain mammals, characterized by regular changes in the reproductive tract and behavior, which are regulated by hormonal fluctuations. It is most commonly observed in non-primate mammals such as dogs, cats, cows, pigs, and horses.

The estrous cycle consists of several stages:

1. Proestrus: This stage lasts for a few days and is characterized by the development of follicles in the ovaries and an increase in estrogen levels. During this time, the female may show signs of sexual receptivity, but will not allow mating to occur.
2. Estrus: This is the period of sexual receptivity, during which the female allows mating to take place. It typically lasts for a few days and is marked by a surge in luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which triggers ovulation.
3. Metestrus: This stage follows ovulation and is characterized by the formation of a corpus luteum, a structure that produces progesterone to support pregnancy. If fertilization does not occur, the corpus luteum will eventually regress, leading to the next phase.
4. Diestrus: This is the final stage of the estrous cycle and can last for several weeks or months. During this time, the female's reproductive tract returns to its resting state, and she is not sexually receptive. If pregnancy has occurred, the corpus luteum will continue to produce progesterone until the placenta takes over this function later in pregnancy.

It's important to note that the human menstrual cycle is different from the estrous cycle. While both cycles involve hormonal fluctuations and changes in the reproductive tract, the menstrual cycle includes a shedding of the uterine lining (menstruation) if fertilization does not occur, which is not a feature of the estrous cycle.

Gonadal steroid hormones, also known as gonadal sex steroids, are hormones that are produced and released by the gonads (i.e., ovaries in women and testes in men). These hormones play a critical role in the development and maintenance of secondary sexual characteristics, reproductive function, and overall health.

The three main classes of gonadal steroid hormones are:

1. Androgens: These are male sex hormones that are primarily produced by the testes but also produced in smaller amounts by the ovaries and adrenal glands. The most well-known androgen is testosterone, which plays a key role in the development of male secondary sexual characteristics such as facial hair, deepening of the voice, and increased muscle mass.
2. Estrogens: These are female sex hormones that are primarily produced by the ovaries but also produced in smaller amounts by the adrenal glands. The most well-known estrogen is estradiol, which plays a key role in the development of female secondary sexual characteristics such as breast development and the menstrual cycle.
3. Progestogens: These are hormones that are produced by the ovaries during the second half of the menstrual cycle and play a key role in preparing the uterus for pregnancy. The most well-known progestogen is progesterone, which also plays a role in maintaining pregnancy and regulating the menstrual cycle.

Gonadal steroid hormones can have significant effects on various physiological processes, including bone density, cognitive function, mood, and sexual behavior. Disorders of gonadal steroid hormone production or action can lead to a range of health problems, including infertility, osteoporosis, and sexual dysfunction.

Bone density refers to the amount of bone mineral content (usually measured in grams) in a given volume of bone (usually measured in cubic centimeters). It is often used as an indicator of bone strength and fracture risk. Bone density is typically measured using dual-energy X-ray absorptiometry (DXA) scans, which provide a T-score that compares the patient's bone density to that of a young adult reference population. A T-score of -1 or above is considered normal, while a T-score between -1 and -2.5 indicates osteopenia (low bone mass), and a T-score below -2.5 indicates osteoporosis (porous bones). Regular exercise, adequate calcium and vitamin D intake, and medication (if necessary) can help maintain or improve bone density and prevent fractures.

Proestrus is a stage in the estrous cycle of animals, specifically referring to the phase preceding estrus (heat) during which follicle development and estrogen production occur. It is characterized by the swelling of the vulva and the onset of behaviors indicating readiness to mate, although the animal is not yet receptive to males. This stage typically lasts around 2-13 days, depending on the species. In humans, this equivalent phase does not exist due to menstrual cycles rather than estrous cycles.

Bone resorption is the process by which bone tissue is broken down and absorbed into the body. It is a normal part of bone remodeling, in which old or damaged bone tissue is removed and new tissue is formed. However, excessive bone resorption can lead to conditions such as osteoporosis, in which bones become weak and fragile due to a loss of density. This process is carried out by cells called osteoclasts, which break down the bone tissue and release minerals such as calcium into the bloodstream.

'Mammary neoplasms, experimental' is not a recognized medical term. However, I can provide definitions for the individual terms:

1. Mammary: Pertaining to the breast or mammary glands in females, which are responsible for milk production.
2. Neoplasms: Abnormal growths of tissue, also known as tumors or masses, that can be benign (non-cancerous) or malignant (cancerous).
3. Experimental: Relating to a scientific experiment or study, typically conducted in a controlled setting to test hypotheses and gather data.

In the context of medical research, 'experimental mammary neoplasms' may refer to artificially induced breast tumors in laboratory animals (such as rats or mice) for the purpose of studying the development, progression, treatment, and prevention of breast cancer. These studies can help researchers better understand the biology of breast cancer and develop new therapies and strategies for its diagnosis and management.

Ovulation is the medical term for the release of a mature egg from an ovary during a woman's menstrual cycle. The released egg travels through the fallopian tube where it may be fertilized by sperm if sexual intercourse has occurred recently. If the egg is not fertilized, it will break down and leave the body along with the uterine lining during menstruation. Ovulation typically occurs around day 14 of a 28-day menstrual cycle, but the timing can vary widely from woman to woman and even from cycle to cycle in the same woman.

During ovulation, there are several physical changes that may occur in a woman's body, such as an increase in basal body temperature, changes in cervical mucus, and mild cramping or discomfort on one side of the lower abdomen (known as mittelschmerz). These symptoms can be used to help predict ovulation and improve the chances of conception.

It's worth noting that some medical conditions, such as polycystic ovary syndrome (PCOS) or premature ovarian failure, may affect ovulation and make it difficult for a woman to become pregnant. In these cases, medical intervention may be necessary to help promote ovulation and increase the chances of conception.

Testosterone is a steroid hormone that belongs to androsten class of hormones. It is primarily secreted by the Leydig cells in the testes of males and, to a lesser extent, by the ovaries and adrenal glands in females. Testosterone is the main male sex hormone and anabolic steroid. It plays a key role in the development of masculine characteristics, such as body hair and muscle mass, and contributes to bone density, fat distribution, red cell production, and sex drive. In females, testosterone contributes to sexual desire and bone health. Testosterone is synthesized from cholesterol and its production is regulated by luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

Body weight is the measure of the force exerted on a scale or balance by an object's mass, most commonly expressed in units such as pounds (lb) or kilograms (kg). In the context of medical definitions, body weight typically refers to an individual's total weight, which includes their skeletal muscle, fat, organs, and bodily fluids.

Healthcare professionals often use body weight as a basic indicator of overall health status, as it can provide insights into various aspects of a person's health, such as nutritional status, metabolic function, and risk factors for certain diseases. For example, being significantly underweight or overweight can increase the risk of developing conditions like malnutrition, diabetes, heart disease, and certain types of cancer.

It is important to note that body weight alone may not provide a complete picture of an individual's health, as it does not account for factors such as muscle mass, bone density, or body composition. Therefore, healthcare professionals often use additional measures, such as body mass index (BMI), waist circumference, and blood tests, to assess overall health status more comprehensively.

The tibia, also known as the shin bone, is the larger of the two bones in the lower leg and part of the knee joint. It supports most of the body's weight and is a major insertion point for muscles that flex the foot and bend the leg. The tibia articulates with the femur at the knee joint and with the fibula and talus bone at the ankle joint. Injuries to the tibia, such as fractures, are common in sports and other activities that put stress on the lower leg.

"Bone" is the hard, dense connective tissue that makes up the skeleton of vertebrate animals. It provides support and protection for the body's internal organs, and serves as a attachment site for muscles, tendons, and ligaments. Bone is composed of cells called osteoblasts and osteoclasts, which are responsible for bone formation and resorption, respectively, and an extracellular matrix made up of collagen fibers and mineral crystals.

Bones can be classified into two main types: compact bone and spongy bone. Compact bone is dense and hard, and makes up the outer layer of all bones and the shafts of long bones. Spongy bone is less dense and contains large spaces, and makes up the ends of long bones and the interior of flat and irregular bones.

The human body has 206 bones in total. They can be further classified into five categories based on their shape: long bones, short bones, flat bones, irregular bones, and sesamoid bones.

"Sex characteristics" refer to the anatomical, chromosomal, and genetic features that define males and females. These include both primary sex characteristics (such as reproductive organs like ovaries or testes) and secondary sex characteristics (such as breasts or facial hair) that typically develop during puberty. Sex characteristics are primarily determined by the presence of either X or Y chromosomes, with XX individuals usually developing as females and XY individuals usually developing as males, although variations and exceptions to this rule do occur.

Anestrus is a term used in veterinary medicine to describe the period of sexual quiescence in female animals, during which they do not exhibit estrous cycles. This phase is characterized by low levels of reproductive hormones and is seen in some species as a part of their natural reproductive cycle, while in others it may indicate an abnormality or underlying health issue.

For example, in dogs, anestrus is the period between heat cycles when the reproductive system is relatively inactive. In contrast, in domestic cats, continuous estrous cycling is the norm, and they do not typically exhibit an anestrus phase.

In some cases, anestrus may be induced by factors such as poor nutrition, stress, or illness, and it can have negative consequences for an animal's reproductive health if it persists for too long. If an animal is experiencing prolonged anestrus or other reproductive issues, it is important to consult with a veterinarian for proper diagnosis and treatment.

The pituitary gland is a small, endocrine gland located at the base of the brain, in the sella turcica of the sphenoid bone. It is often called the "master gland" because it controls other glands and makes the hormones that trigger many body functions. The pituitary gland measures about 0.5 cm in height and 1 cm in width, and it weighs approximately 0.5 grams.

The pituitary gland is divided into two main parts: the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis). The anterior lobe is further divided into three zones: the pars distalis, pars intermedia, and pars tuberalis. Each part of the pituitary gland has distinct functions and produces different hormones.

The anterior pituitary gland produces and releases several important hormones, including:

* Growth hormone (GH), which regulates growth and development in children and helps maintain muscle mass and bone strength in adults.
* Thyroid-stimulating hormone (TSH), which controls the production of thyroid hormones by the thyroid gland.
* Adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands to produce cortisol and other steroid hormones.
* Follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which regulate reproductive function in both males and females.
* Prolactin, which stimulates milk production in pregnant and lactating women.

The posterior pituitary gland stores and releases two hormones that are produced by the hypothalamus:

* Antidiuretic hormone (ADH), which helps regulate water balance in the body by controlling urine production.
* Oxytocin, which stimulates uterine contractions during childbirth and milk release during breastfeeding.

Overall, the pituitary gland plays a critical role in maintaining homeostasis and regulating various bodily functions, including growth, development, metabolism, and reproductive function.

Metabolic bone diseases are a group of conditions that affect the bones and are caused by disorders in the body's metabolism. These disorders can result in changes to the bone structure, density, and strength, leading to an increased risk of fractures and other complications. Some common examples of metabolic bone diseases include:

1. Osteoporosis: a condition characterized by weak and brittle bones that are more likely to break, often as a result of age-related bone loss or hormonal changes.
2. Paget's disease of bone: a chronic disorder that causes abnormal bone growth and deformities, leading to fragile and enlarged bones.
3. Osteomalacia: a condition caused by a lack of vitamin D or problems with the body's ability to absorb it, resulting in weak and soft bones.
4. Hyperparathyroidism: a hormonal disorder that causes too much parathyroid hormone to be produced, leading to bone loss and other complications.
5. Hypoparathyroidism: a hormonal disorder that results in low levels of parathyroid hormone, causing weak and brittle bones.
6. Renal osteodystrophy: a group of bone disorders that occur as a result of chronic kidney disease, including osteomalacia, osteoporosis, and high turnover bone disease.

Treatment for metabolic bone diseases may include medications to improve bone density and strength, dietary changes, exercise, and lifestyle modifications. In some cases, surgery may be necessary to correct bone deformities or fractures.

Perphenazine is an antipsychotic medication that belongs to the class of phenothiazines. It works by blocking dopamine receptors in the brain, which helps to reduce psychotic symptoms such as delusions, hallucinations, and disordered thinking. Perphenazine is used to treat various mental disorders, including schizophrenia, psychotic disorders, and severe agitation or aggression in people with developmental disabilities. It may also be used for the short-term treatment of severe anxiety or depression that does not respond to other treatments.

Perphenazine can cause side effects such as drowsiness, dizziness, restlessness, dry mouth, constipation, and weight gain. More serious side effects may include neurological symptoms such as tremors, stiffness, and uncontrolled muscle movements, which may indicate a condition called tardive dyskinesia. Perphenazine can also cause cardiovascular side effects such as low blood pressure, irregular heartbeat, and increased heart rate. It is important to monitor patients taking perphenazine for these and other potential side effects.

It's worth noting that the use of antipsychotic medications like perphenazine should be based on a thorough evaluation of the patient's symptoms, medical history, and other factors. The decision to prescribe this medication should be made carefully, taking into account its benefits and risks, as well as any alternative treatment options.

Prolactin is a hormone produced by the pituitary gland, a small gland located at the base of the brain. Its primary function is to stimulate milk production in women after childbirth, a process known as lactation. However, prolactin also plays other roles in the body, including regulating immune responses, metabolism, and behavior. In men, prolactin helps maintain the sexual glands and contributes to paternal behaviors.

Prolactin levels are usually low in both men and non-pregnant women but increase significantly during pregnancy and after childbirth. Various factors can affect prolactin levels, including stress, sleep, exercise, and certain medications. High prolactin levels can lead to medical conditions such as amenorrhea (absence of menstruation), galactorrhea (spontaneous milk production not related to childbirth), infertility, and reduced sexual desire in both men and women.

Pregnancy is a physiological state or condition where a fertilized egg (zygote) successfully implants and grows in the uterus of a woman, leading to the development of an embryo and finally a fetus. This process typically spans approximately 40 weeks, divided into three trimesters, and culminates in childbirth. Throughout this period, numerous hormonal and physical changes occur to support the growing offspring, including uterine enlargement, breast development, and various maternal adaptations to ensure the fetus's optimal growth and well-being.

A drug implant is a medical device that is specially designed to provide controlled release of a medication into the body over an extended period of time. Drug implants can be placed under the skin or in various body cavities, depending on the specific medical condition being treated. They are often used when other methods of administering medication, such as oral pills or injections, are not effective or practical.

Drug implants come in various forms, including rods, pellets, and small capsules. The medication is contained within the device and is released slowly over time, either through diffusion or erosion of the implant material. This allows for a steady concentration of the drug to be maintained in the body, which can help to improve treatment outcomes and reduce side effects.

Some common examples of drug implants include:

1. Hormonal implants: These are small rods that are inserted under the skin of the upper arm and release hormones such as progestin or estrogen over a period of several years. They are often used for birth control or to treat conditions such as endometriosis or uterine fibroids.
2. Intraocular implants: These are small devices that are placed in the eye during surgery to release medication directly into the eye. They are often used to treat conditions such as age-related macular degeneration or diabetic retinopathy.
3. Bone cement implants: These are specially formulated cements that contain antibiotics and are used to fill bone defects or joint spaces during surgery. The antibiotics are released slowly over time, helping to prevent infection.
4. Implantable pumps: These are small devices that are placed under the skin and deliver medication directly into a specific body cavity, such as the spinal cord or the peritoneal cavity. They are often used to treat chronic pain or cancer.

Overall, drug implants offer several advantages over other methods of administering medication, including improved compliance, reduced side effects, and more consistent drug levels in the body. However, they may also have some disadvantages, such as the need for surgical placement and the potential for infection or other complications. As with any medical treatment, it is important to discuss the risks and benefits of drug implants with a healthcare provider.

Estrogen Receptor alpha (ERα) is a type of nuclear receptor protein that is activated by the hormone estrogen. It is encoded by the gene ESR1 and is primarily expressed in the cells of the reproductive system, breast, bone, liver, heart, and brain tissue.

When estrogen binds to ERα, it causes a conformational change in the receptor, which allows it to dimerize and translocate to the nucleus. Once in the nucleus, ERα functions as a transcription factor, binding to specific DNA sequences called estrogen response elements (EREs) and regulating the expression of target genes.

ERα plays important roles in various physiological processes, including the development and maintenance of female reproductive organs, bone homeostasis, and lipid metabolism. It is also a critical factor in the growth and progression of certain types of breast cancer, making ERα status an important consideration in the diagnosis and treatment of this disease.

Orchiectomy is a surgical procedure where one or both of the testicles are removed. It is also known as castration. This procedure can be performed for various reasons, including the treatment of testicular cancer, prostate cancer, or other conditions that may affect the testicles. It can also be done to reduce levels of male hormones in the body, such as in the case of transgender women undergoing gender affirming surgery. The specific medical definition may vary slightly depending on the context and the extent of the procedure.

"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.

Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.

Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.

An ovarian follicle is a fluid-filled sac in the ovary that contains an immature egg or ovum (oocyte). It's a part of the female reproductive system and plays a crucial role in the process of ovulation.

Ovarian follicles start developing in the ovaries during fetal development, but only a small number of them will mature and release an egg during a woman's reproductive years. The maturation process is stimulated by hormones like follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

There are different types of ovarian follicles, including primordial, primary, secondary, and tertiary or Graafian follicles. The Graafian follicle is the mature follicle that ruptures during ovulation to release the egg into the fallopian tube, where it may be fertilized by sperm.

It's important to note that abnormal growth or development of ovarian follicles can lead to conditions like polycystic ovary syndrome (PCOS) and ovarian cancer.

Metestrus is the second phase of the estrous cycle in animals, specifically referring to the period of sexual receptivity and ovulation. In humans, this phase corresponds to the luteal phase of the menstrual cycle. During metestrus, the corpus luteum, a temporary endocrine structure formed from the remains of the ovarian follicle after ovulation, produces progesterone, which prepares the uterus for potential implantation of a fertilized egg. The duration of metestrus varies among species and can last several days to a few weeks. It is followed by diestrus, the final phase of the estrous cycle, during which the corpus luteum regresses, and hormone levels drop, leading to the shedding of the uterine lining in non-pregnant individuals.

Estrogen Receptor beta (ER-β) is a protein that is encoded by the gene ESR2 in humans. It belongs to the family of nuclear receptors, which are transcription factors that regulate gene expression in response to hormonal signals. ER-β is one of two main estrogen receptors, the other being Estrogen Receptor alpha (ER-α), and it plays an important role in mediating the effects of estrogens in various tissues, including the breast, uterus, bone, brain, and cardiovascular system.

Estrogens are steroid hormones that play a critical role in the development and maintenance of female reproductive and sexual function. They also have important functions in other tissues, such as maintaining bone density and promoting cognitive function. ER-β is widely expressed in many tissues, including those outside of the reproductive system, suggesting that it may have diverse physiological roles beyond estrogen-mediated reproduction.

ER-β has been shown to have both overlapping and distinct functions from ER-α, and its expression patterns differ between tissues. For example, in the breast, ER-β is expressed at higher levels in normal tissue compared to cancerous tissue, suggesting that it may play a protective role against breast cancer development. In contrast, in the uterus, ER-β has been shown to have anti-proliferative effects and may protect against endometrial cancer.

Overall, ER-β is an important mediator of estrogen signaling and has diverse physiological roles in various tissues. Understanding its functions and regulation may provide insights into the development of novel therapies for a range of diseases, including cancer, osteoporosis, and cardiovascular disease.

Methylnitrosourea (MNU) is not a medical term per se, but it is a chemical compound that has been widely used in biomedical research, particularly in cancer studies. Therefore, I will provide you with a scientific definition of this compound.

Methylnitrosourea (MNU) is an alkylating agent and a nitrosourea compound. It is known to be highly mutagenic and carcinogenic. MNU acts by transferring its methyl group (-CH3) to DNA, RNA, and proteins, causing damage to these macromolecules. This methylation can lead to point mutations, chromosomal aberrations, and DNA strand breaks, which contribute to genomic instability and cancer initiation and progression.

In research settings, MNU has been used as a model carcinogen to induce tumors in various animal models, primarily rodents, to study the mechanisms of carcinogenesis and evaluate potential chemopreventive or therapeutic agents. However, due to its high toxicity and mutagenicity, handling and use of MNU require strict safety measures and precautions.

I apologize, but "sheep" is not a term that has a medical definition. It is a common animal with the scientific name Ovis aries. If you have any medical or health-related questions, I would be happy to try and help answer those for you.

Norpregnenes are a class of steroids that are produced by the metabolism of progesterone and other pregnanes. They are characterized by the absence of a double bond between carbons 4 and 5, and the presence of a ketone group at carbon 3. Some examples of norpregnenes include dehydroepiandrosterone (DHEA), androstenedione, and pregnenolone. These steroids are important intermediates in the biosynthesis of various hormones, including cortisol, aldosterone, androgens, and estrogens. They play a role in various physiological processes such as sexual development, immune function, and stress response.

A tooth socket, also known as an alveolus (plural: alveoli), refers to the hollow cavity or space in the jawbone where a tooth is anchored. The tooth socket is part of the alveolar process, which is the curved part of the maxilla or mandible that contains multiple tooth sockets for the upper and lower teeth, respectively.

Each tooth socket has a specialized tissue called the periodontal ligament, which attaches the root of the tooth to the surrounding bone. This ligament helps absorb forces generated during biting and chewing, allowing for comfortable and efficient mastication while also maintaining the tooth's position within the jawbone. The tooth socket is responsible for providing support, stability, and nourishment to the tooth through its blood vessels and nerves.

X-ray microtomography, often referred to as micro-CT, is a non-destructive imaging technique used to visualize and analyze the internal structure of objects with high spatial resolution. It is based on the principles of computed tomography (CT), where multiple X-ray images are acquired at different angles and then reconstructed into cross-sectional slices using specialized software. These slices can be further processed to create 3D visualizations, allowing researchers and clinicians to examine the internal structure and composition of samples in great detail. Micro-CT is widely used in materials science, biology, medicine, and engineering for various applications such as material characterization, bone analysis, and defect inspection.

Gonadotropin-Releasing Hormone (GnRH), also known as Luteinizing Hormone-Releasing Hormone (LHRH), is a hormonal peptide consisting of 10 amino acids. It is produced and released by the hypothalamus, an area in the brain that links the nervous system to the endocrine system via the pituitary gland.

GnRH plays a crucial role in regulating reproduction and sexual development through its control of two gonadotropins: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These gonadotropins, in turn, stimulate the gonads (ovaries or testes) to produce sex steroids and eggs or sperm.

GnRH acts on the anterior pituitary gland by binding to its specific receptors, leading to the release of FSH and LH. The hypothalamic-pituitary-gonadal axis is under negative feedback control, meaning that when sex steroid levels are high, they inhibit the release of GnRH, which subsequently decreases FSH and LH secretion.

GnRH agonists and antagonists have clinical applications in various medical conditions, such as infertility treatments, precocious puberty, endometriosis, uterine fibroids, prostate cancer, and hormone-responsive breast cancer.

Estrogen receptors (ERs) are a type of nuclear receptor protein that are expressed in various tissues and cells throughout the body. They play a critical role in the regulation of gene expression and cellular responses to the hormone estrogen. There are two main subtypes of ERs, ERα and ERβ, which have distinct molecular structures, expression patterns, and functions.

ERs function as transcription factors that bind to specific DNA sequences called estrogen response elements (EREs) in the promoter regions of target genes. When estrogen binds to the ER, it causes a conformational change in the receptor that allows it to recruit co-activator proteins and initiate transcription of the target gene. This process can lead to a variety of cellular responses, including changes in cell growth, differentiation, and metabolism.

Estrogen receptors are involved in a wide range of physiological processes, including the development and maintenance of female reproductive tissues, bone homeostasis, cardiovascular function, and cognitive function. They have also been implicated in various pathological conditions, such as breast cancer, endometrial cancer, and osteoporosis. As a result, ERs are an important target for therapeutic interventions in these diseases.

Raloxifene is a selective estrogen receptor modulator (SERM) that is used in the prevention and treatment of osteoporosis in postmenopausal women. It works by mimicking the effects of estrogen on some tissues, such as bones, while blocking its effects on others, such as breast tissue. This can help to reduce the risk of fractures and breast cancer in postmenopausal women with osteoporosis.

Raloxifene is available in tablet form and is typically taken once a day. Common side effects include hot flashes, leg cramps, and sweating. It may also increase the risk of blood clots, so it is important to discuss any history of blood clots or other medical conditions with your healthcare provider before starting treatment with raloxifene.

It's important to note that Raloxifene should not be used in premenopausal women or in men, and it should not be taken during pregnancy or while breastfeeding. It is also important to follow the dosage instructions carefully and to discuss any concerns with your healthcare provider before taking this medication.

"Inbred strains of rats" are genetically identical rodents that have been produced through many generations of brother-sister mating. This results in a high degree of homozygosity, where the genes at any particular locus in the genome are identical in all members of the strain.

Inbred strains of rats are widely used in biomedical research because they provide a consistent and reproducible genetic background for studying various biological phenomena, including the effects of drugs, environmental factors, and genetic mutations on health and disease. Additionally, inbred strains can be used to create genetically modified models of human diseases by introducing specific mutations into their genomes.

Some commonly used inbred strains of rats include the Wistar Kyoto (WKY), Sprague-Dawley (SD), and Fischer 344 (F344) rat strains. Each strain has its own unique genetic characteristics, making them suitable for different types of research.

Estrogen antagonists, also known as antiestrogens, are a class of drugs that block the effects of estrogen in the body. They work by binding to estrogen receptors and preventing the natural estrogen from attaching to them. This results in the inhibition of estrogen-mediated activities in various tissues, including breast and uterine tissue.

There are two main types of estrogen antagonists: selective estrogen receptor modulators (SERMs) and pure estrogen receptor downregulators (PERDS), also known as estrogen receptor downregulators (ERDs). SERMs, such as tamoxifen and raloxifene, can act as estrogen agonists or antagonists depending on the tissue type. For example, they may block the effects of estrogen in breast tissue while acting as an estrogen agonist in bone tissue, helping to prevent osteoporosis.

PERDS, such as fulvestrant, are pure estrogen receptor antagonists and do not have any estrogen-like activity. They are used primarily for the treatment of hormone receptor-positive breast cancer in postmenopausal women.

Overall, estrogen antagonists play an important role in the management of hormone receptor-positive breast cancer and other conditions where inhibiting estrogen activity is beneficial.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Bone remodeling is the normal and continuous process by which bone tissue is removed from the skeleton (a process called resorption) and new bone tissue is formed (a process called formation). This ongoing cycle allows bones to repair microdamage, adjust their size and shape in response to mechanical stress, and maintain mineral homeostasis. The cells responsible for bone resorption are osteoclasts, while the cells responsible for bone formation are osteoblasts. These two cell types work together to maintain the structural integrity and health of bones throughout an individual's life.

During bone remodeling, the process can be divided into several stages:

1. Activation: The initiation of bone remodeling is triggered by various factors such as microdamage, hormonal changes, or mechanical stress. This leads to the recruitment and activation of osteoclast precursor cells.
2. Resorption: Osteoclasts attach to the bone surface and create a sealed compartment called a resorption lacuna. They then secrete acid and enzymes that dissolve and digest the mineralized matrix, creating pits or cavities on the bone surface. This process helps remove old or damaged bone tissue and releases calcium and phosphate ions into the bloodstream.
3. Reversal: After resorption is complete, the osteoclasts undergo apoptosis (programmed cell death), and mononuclear cells called reversal cells appear on the resorbed surface. These cells prepare the bone surface for the next stage by cleaning up debris and releasing signals that attract osteoblast precursors.
4. Formation: Osteoblasts, derived from mesenchymal stem cells, migrate to the resorbed surface and begin producing a new organic matrix called osteoid. As the osteoid mineralizes, it forms a hard, calcified structure that gradually replaces the resorbed bone tissue. The osteoblasts may become embedded within this newly formed bone as they differentiate into osteocytes, which are mature bone cells responsible for maintaining bone homeostasis and responding to mechanical stress.
5. Mineralization: Over time, the newly formed bone continues to mineralize, becoming stronger and more dense. This process helps maintain the structural integrity of the skeleton and ensures adequate calcium storage.

Throughout this continuous cycle of bone remodeling, hormones, growth factors, and mechanical stress play crucial roles in regulating the balance between resorption and formation. Disruptions to this delicate equilibrium can lead to various bone diseases, such as osteoporosis, where excessive resorption results in weakened bones and increased fracture risk.

9,10-Dimethyl-1,2-benzanthracene (DMBA) is a synthetic, aromatic hydrocarbon that is commonly used in research as a carcinogenic compound. It is a potent tumor initiator and has been widely used to study chemical carcinogenesis in laboratory animals.

DMBA is a polycyclic aromatic hydrocarbon (PAH) with two benzene rings fused together, and two methyl groups attached at the 9 and 10 positions. This structure allows DMBA to intercalate into DNA, causing mutations that can lead to cancer.

Exposure to DMBA has been shown to cause a variety of tumors in different organs, depending on the route of administration and dose. In animal models, DMBA is often applied to the skin or administered orally to induce tumors in the mammary glands, lungs, or digestive tract.

It's important to note that DMBA is not a natural compound found in the environment and is used primarily for research purposes only. It should be handled with care and appropriate safety precautions due to its carcinogenic properties.

I'm sorry for any confusion, but the term "metrial gland" does not have a recognized medical definition. It seems there might be some misunderstanding or misspelling in your query. If you intended to ask about "mammary glands," which are the milk-producing organs found in female mammals, I would be happy to provide more information on those!

Gonadotropins are hormones produced and released by the anterior pituitary gland, a small endocrine gland located at the base of the brain. These hormones play crucial roles in regulating reproduction and sexual development. There are two main types of gonadotropins:

1. Follicle-Stimulating Hormone (FSH): FSH is essential for the growth and development of follicles in the ovaries (in females) or sperm production in the testes (in males). In females, FSH stimulates the maturation of eggs within the follicles.
2. Luteinizing Hormone (LH): LH triggers ovulation in females, causing the release of a mature egg from the dominant follicle. In males, LH stimulates the production and secretion of testosterone in the testes.

Together, FSH and LH work synergistically to regulate various aspects of reproductive function and sexual development. Their secretion is controlled by the hypothalamus, which releases gonadotropin-releasing hormone (GnRH) to stimulate the production and release of FSH and LH from the anterior pituitary gland.

Abnormal levels of gonadotropins can lead to various reproductive disorders, such as infertility or menstrual irregularities in females and issues related to sexual development or function in both sexes. In some cases, synthetic forms of gonadotropins may be used clinically to treat these conditions or for assisted reproductive technologies (ART).

Alendronate is a medication that falls under the class of bisphosphonates. It is commonly used in the treatment and prevention of osteoporosis in postmenopausal women and men, as well as in the management of glucocorticoid-induced osteoporosis and Paget's disease of bone.

Alendronate works by inhibiting the activity of osteoclasts, which are cells responsible for breaking down and reabsorbing bone tissue. By reducing the activity of osteoclasts, alendronate helps to slow down bone loss and increase bone density, thereby reducing the risk of fractures.

The medication is available in several forms, including tablets and oral solutions, and is typically taken once a week for osteoporosis prevention and treatment. It is important to follow the dosing instructions carefully, as improper administration can reduce the drug's effectiveness or increase the risk of side effects. Common side effects of alendronate include gastrointestinal symptoms such as heartburn, stomach pain, and nausea.

Pseudopregnancy, also known as pseudocyesis or phantom pregnancy, is a psychological condition where an individual (most commonly in women) believes they are pregnant when they are not. This belief is often accompanied by various physical symptoms such as weight gain, abdominal distention, and breast enlargement that mimic those of a genuine pregnancy, despite there being no actual fetal development. These symptoms are caused by the body's hormonal and physiological responses to the individual's strong belief of being pregnant. It is important to note that this condition is rare and can be resolved with proper medical evaluation, counseling, and support.

Gastric dilatation, also known as stomach dilation or distention, refers to the abnormal enlargement or expansion of the stomach. This condition often occurs when the stomach fills with gas, food, or fluids and is unable to empty properly. Gastric dilatation can be caused by various factors such as overeating, swallowing excessive air, gastroparesis (delayed gastric emptying), intestinal obstruction, or certain medical conditions like hiatal hernia or pregnancy.

In severe cases, gastric dilatation may lead to gastric volvulus, where the stomach twists on itself, cutting off its blood supply and leading to ischemia and necrosis of the stomach tissue. This is a life-threatening condition that requires immediate medical attention. Symptoms of gastric dilatation include abdominal pain, bloating, vomiting, loss of appetite, and difficulty breathing.

Aging is a complex, progressive and inevitable process of bodily changes over time, characterized by the accumulation of cellular damage and degenerative changes that eventually lead to increased vulnerability to disease and death. It involves various biological, genetic, environmental, and lifestyle factors that contribute to the decline in physical and mental functions. The medical field studies aging through the discipline of gerontology, which aims to understand the underlying mechanisms of aging and develop interventions to promote healthy aging and extend the human healthspan.

Mammary glands are specialized exocrine glands found in mammals, including humans and other animals. These glands are responsible for producing milk, which is used to nurse offspring after birth. The mammary glands are located in the breast region of female mammals and are usually rudimentary or absent in males.

In animals, mammary glands can vary in number and location depending on the species. For example, humans and other primates have two mammary glands, one in each breast. Cows, goats, and sheep, on the other hand, have multiple pairs of mammary glands located in their lower abdominal region.

Mammary glands are made up of several structures, including lobules, ducts, and connective tissue. The lobules contain clusters of milk-secreting cells called alveoli, which produce and store milk. The ducts transport the milk from the lobules to the nipple, where it is released during lactation.

Mammary glands are an essential feature of mammals, as they provide a source of nutrition for newborn offspring. They also play a role in the development and maintenance of the mother-infant bond, as nursing provides opportunities for physical contact and bonding between the mother and her young.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

Phytoestrogens are compounds found in plants that have estrogen-like properties. They can bind to and activate or inhibit the action of estrogen receptors in the body, depending on their structure and concentration. Phytoestrogens are present in a variety of foods, including soy products, nuts, seeds, fruits, and vegetables.

Phytoestrogens have been studied for their potential health benefits, such as reducing the risk of hormone-dependent cancers (e.g., breast cancer), improving menopausal symptoms, and promoting bone health. However, their effects on human health are complex and not fully understood, and some studies suggest that high intake of phytoestrogens may have adverse effects in certain populations or under specific conditions.

It is important to note that while phytoestrogens can mimic the effects of estrogen in the body, they are generally weaker than endogenous estrogens produced by the human body. Therefore, their impact on hormonal balance and health outcomes may vary depending on individual factors such as age, sex, hormonal status, and overall diet.

Delayed embryo implantation is a medical condition that occurs when the fertilized egg (embryo) does not attach to the uterine lining (endometrium) within the expected time frame, typically within 7-10 days after ovulation. In delayed implantation, the embryo may take longer than usual to implant, which can result in a prolonged menstrual cycle or irregular bleeding.

There are several possible reasons for delayed implantation, including hormonal imbalances, uterine abnormalities, immune system dysfunction, and chromosomal abnormalities in the embryo. In some cases, delayed implantation may be a sign of infertility or recurrent pregnancy loss.

Diagnosis of delayed implantation typically involves monitoring hormone levels and tracking menstrual cycles. Imaging tests such as ultrasound or hysteroscopy may also be used to assess the uterine lining and detect any abnormalities that could be contributing to the delay in implantation.

Treatment for delayed implantation depends on the underlying cause. Hormonal therapies, medications to suppress the immune system, or surgery to correct uterine abnormalities may be recommended in some cases. In vitro fertilization (IVF) with embryo transfer may also be considered as a treatment option for couples experiencing delayed implantation and infertility.

Medroxyprogesterone is a synthetic form of the natural hormone progesterone, which is a female sex hormone produced by the corpus luteum during the menstrual cycle and by the placenta during pregnancy. As a medication, medroxyprogesterone is used to treat a variety of conditions, including:

* Abnormal menstrual bleeding
* Endometrial hyperplasia (overgrowth of the lining of the uterus)
* Contraception (birth control)
* Hormone replacement therapy in postmenopausal women
* Prevention of breast cancer in high-risk women
* Treatment of certain types of cancer, such as endometrial and renal cancers

Medroxyprogesterone works by binding to progesterone receptors in the body, which helps to regulate the menstrual cycle, maintain pregnancy, and prevent the growth of some types of cancer. It is available in various forms, including tablets, injectable solutions, and depot suspensions for intramuscular injection.

It's important to note that medroxyprogesterone can have significant side effects, and its use should be monitored by a healthcare provider. Women who are pregnant or breastfeeding should not take medroxyprogesterone, and it may interact with other medications, so it is important to inform your doctor of all medications you are taking before starting medroxyprogesterone.

Maprotiline is a tetracyclic antidepressant (TCA) medication that is primarily used to treat major depressive disorder. It works by increasing the levels of neurotransmitters, such as norepinephrine and serotonin, in the brain, which can help to improve mood and alleviate symptoms of depression.

Maprotiline has a unique chemical structure that distinguishes it from other antidepressants, including selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs). It is considered to be a second-line treatment option for depression, typically reserved for use when other antidepressants have not been effective.

Like other TCAs, maprotiline can cause a range of side effects, including dry mouth, blurred vision, constipation, and dizziness. It may also cause more serious side effects, such as seizures, irregular heartbeat, and changes in blood pressure. As a result, it is important to use maprotiline under the close supervision of a healthcare provider.

Maprotiline is available in tablet form and is typically taken two to four times per day, with or without food. The dosage may be gradually increased over time to achieve the desired therapeutic effect. It may take several weeks of treatment before the full benefits of maprotiline are felt.

Inhibins are a group of protein hormones that play a crucial role in regulating the function of the reproductive system, specifically by inhibiting the production of follicle-stimulating hormone (FSH) in the pituitary gland. They are produced and secreted primarily by the granulosa cells in the ovaries of females and Sertoli cells in the testes of males.

Inhibins consist of two subunits, an alpha subunit, and a beta subunit, which can be further divided into two types: inhibin A and inhibin B. Inhibin A is primarily produced by the granulosa cells of developing follicles in the ovary, while inhibin B is mainly produced by the Sertoli cells in the testes.

By regulating FSH production, inhibins help control the development and maturation of ovarian follicles in females and spermatogenesis in males. Abnormal levels of inhibins have been associated with various reproductive disorders, including polycystic ovary syndrome (PCOS) and certain types of cancer.

C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.

The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.

C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.

One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.

Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.

Osteoclasts are large, multinucleated cells that are primarily responsible for bone resorption, a process in which they break down and dissolve the mineralized matrix of bones. They are derived from monocyte-macrophage precursor cells of hematopoietic origin and play a crucial role in maintaining bone homeostasis by balancing bone formation and bone resorption.

Osteoclasts adhere to the bone surface and create an isolated microenvironment, called the "resorption lacuna," between their cell membrane and the bone surface. Here, they release hydrogen ions into the lacuna through a process called proton pumping, which lowers the pH and dissolves the mineral component of the bone matrix. Additionally, osteoclasts secrete proteolytic enzymes, such as cathepsin K, that degrade the organic components, like collagen, in the bone matrix.

An imbalance in osteoclast activity can lead to various bone diseases, including osteoporosis and Paget's disease, where excessive bone resorption results in weakened and fragile bones.

"Random allocation," also known as "random assignment" or "randomization," is a process used in clinical trials and other research studies to distribute participants into different intervention groups (such as experimental group vs. control group) in a way that minimizes selection bias and ensures the groups are comparable at the start of the study.

In random allocation, each participant has an equal chance of being assigned to any group, and the assignment is typically made using a computer-generated randomization schedule or other objective methods. This process helps to ensure that any differences between the groups are due to the intervention being tested rather than pre-existing differences in the participants' characteristics.

In a medical context, feedback refers to the information or data about the results of a process, procedure, or treatment that is used to evaluate and improve its effectiveness. This can include both quantitative data (such as vital signs or laboratory test results) and qualitative data (such as patient-reported symptoms or satisfaction). Feedback can come from various sources, including patients, healthcare providers, medical equipment, and electronic health records. It is an essential component of quality improvement efforts, allowing healthcare professionals to make informed decisions about changes to care processes and treatments to improve patient outcomes.

'Ovum transport' refers to the movement of an egg or ovum from the mature follicle within the ovary, through the fallopian tube, and ultimately to the uterus. This process is a critical part of the female reproductive system and occurs during each menstrual cycle.

The ovulation phase of the menstrual cycle triggers the release of a mature egg from the follicle in the ovary. The fimbriated end of the fallopian tube captures the egg and transports it into the tube, where it may encounter sperm for fertilization. Cilia lining the inside of the fallopian tubes create wave-like motions that help propel the egg towards the uterus.

If fertilization occurs, the resulting zygote will continue to travel down the fallopian tube and implant itself into the uterine lining, initiating pregnancy. If fertilization does not occur, the egg will be shed along with the uterine lining during menstruation.

The Harderian gland is a specialized exocrine gland located in many vertebrate species, including birds and mammals. In humans, it is rudimentary and not fully developed. However, in other animals like rodents, lagomorphs (rabbits and hares), and some reptiles, this gland plays a significant role.

The Harderian gland is primarily responsible for producing and secreting lipids, which help to lubricate the eye's surface and the nictitating membrane (third eyelid). This lubrication ensures that the eyes remain moist and protected from dryness and external irritants. Additionally, the secretions of the Harderian gland contain immunoglobulins, which contribute to the animal's immune defense system by providing protection against pathogens.

In some animals, the Harderian gland also has a role in pheromone production and communication. The study and understanding of this gland are particularly important in toxicological research, as it is often used as an indicator of environmental pollutant exposure and their effects on wildlife.

Bone density conservation agents, also known as anti-resorptive agents or bone-sparing drugs, are a class of medications that help to prevent the loss of bone mass and reduce the risk of fractures. They work by inhibiting the activity of osteoclasts, the cells responsible for breaking down and reabsorbing bone tissue during the natural remodeling process.

Examples of bone density conservation agents include:

1. Bisphosphonates (e.g., alendronate, risedronate, ibandronate, zoledronic acid) - These are the most commonly prescribed class of bone density conservation agents. They bind to hydroxyapatite crystals in bone tissue and inhibit osteoclast activity, thereby reducing bone resorption.
2. Denosumab (Prolia) - This is a monoclonal antibody that targets RANKL (Receptor Activator of Nuclear Factor-κB Ligand), a key signaling molecule involved in osteoclast differentiation and activation. By inhibiting RANKL, denosumab reduces osteoclast activity and bone resorption.
3. Selective estrogen receptor modulators (SERMs) (e.g., raloxifene) - These medications act as estrogen agonists or antagonists in different tissues. In bone tissue, SERMs mimic the bone-preserving effects of estrogen by inhibiting osteoclast activity and reducing bone resorption.
4. Hormone replacement therapy (HRT) - Estrogen hormone replacement therapy has been shown to preserve bone density in postmenopausal women; however, its use is limited due to increased risks of breast cancer, cardiovascular disease, and thromboembolic events.
5. Calcitonin - This hormone, secreted by the thyroid gland, inhibits osteoclast activity and reduces bone resorption. However, it has largely been replaced by other more effective bone density conservation agents.

These medications are often prescribed for individuals at high risk of fractures due to conditions such as osteoporosis or metabolic disorders that affect bone health. It is essential to follow the recommended dosage and administration guidelines to maximize their benefits while minimizing potential side effects. Regular monitoring of bone density, blood calcium levels, and other relevant parameters is also necessary during treatment with these medications.

The vagina is the canal that joins the cervix (the lower part of the uterus) to the outside of the body. It also is known as the birth canal because babies pass through it during childbirth. The vagina is where sexual intercourse occurs and where menstrual blood exits the body. It has a flexible wall that can expand and retract. During sexual arousal, the vaginal walls swell with blood to become more elastic in order to accommodate penetration.

It's important to note that sometimes people use the term "vagina" to refer to the entire female genital area, including the external structures like the labia and clitoris. But technically, these are considered part of the vulva, not the vagina.

The term "stifle" is commonly used in veterinary medicine to refer to the joint in the leg of animals, specifically the knee joint in quadrupeds such as dogs and horses. In human anatomy, this joint is called the patellofemoral joint or knee joint. The stifle is a complex joint made up of several bones, including the femur, tibia, and patella (kneecap), as well as various ligaments, tendons, and cartilage that provide stability and support. Injuries or diseases affecting the stifle can cause lameness, pain, and decreased mobility in animals.

Pituitary hormone-releasing hormones (PRHs), also known as hypothalamic releasing hormones or hypothalamic hormones, are small neuropeptides produced and released by the hypothalamus - a small region of the brain. These hormones play crucial roles in regulating the secretion and release of various pituitary hormones, which in turn control several essential bodily functions, including growth, development, metabolism, stress response, reproduction, and lactation.

There are several PRHs, each with a specific target pituitary hormone:

1. Thyrotropin-releasing hormone (TRH): Stimulates the release of thyroid-stimulating hormone (TSH) from the anterior pituitary gland, which then promotes the production and release of thyroid hormones.
2. Gonadotropin-releasing hormone (GnRH): Regulates the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland, which are essential for reproductive functions.
3. Corticotropin-releasing hormone (CRH): Stimulates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland, which then promotes the production and release of cortisol and other glucocorticoids from the adrenal glands.
4. Growth hormone-releasing hormone (GHRH): Stimulates the release of growth hormone (GH) from the anterior pituitary gland, which is essential for growth, development, and metabolism regulation.
5. Somatostatin or growth hormone-inhibiting hormone (GHIH): Inhibits the release of GH from the anterior pituitary gland and also suppresses the secretion of thyroid hormones.
6. Prolactin-releasing hormone (PRH) or prolactin-releasing factor (PRF): Stimulates the release of prolactin from the anterior pituitary gland, which is essential for lactation and reproductive functions.
7. Prolactin-inhibiting hormone (PIH) or dopamine: Inhibits the release of prolactin from the anterior pituitary gland.

These releasing hormones and inhibitory hormones work together to maintain a delicate balance in various physiological processes, including growth, development, metabolism, stress response, and reproductive functions. Dysregulation of these hormonal systems can lead to various endocrine disorders and diseases.

"Cissus" is a genus of plants in the grape family, Vitaceae. It includes around 350 species of woody vines and shrubs that are found primarily in tropical regions around the world. Some species of Cissus have been used in traditional medicine for various purposes, including wound healing and treating bone fractures. However, it is important to note that the use of these plants as a medical treatment should be done under the guidance of a healthcare professional, as they can also have side effects and interact with other medications.

The corpus luteum is a temporary endocrine structure that forms in the ovary after an oocyte (egg) has been released from a follicle during ovulation. It's formed by the remaining cells of the ruptured follicle, which transform into large, hormone-secreting cells.

The primary function of the corpus luteum is to produce progesterone and, to a lesser extent, estrogen during the menstrual cycle or pregnancy. Progesterone plays a crucial role in preparing the uterus for potential implantation of a fertilized egg and maintaining the early stages of pregnancy. If pregnancy does not occur, the corpus luteum will typically degenerate and stop producing hormones after approximately 10-14 days, leading to menstruation.

However, if pregnancy occurs, the developing embryo starts to produce human chorionic gonadotropin (hCG), which signals the corpus luteum to continue secreting progesterone and estrogen until the placenta takes over hormonal production, usually around the end of the first trimester.

Postmenopausal osteoporosis is a specific type of osteoporosis that occurs in women after they have gone through menopause. It is defined as a skeletal disorder characterized by compromised bone strength, leading to an increased risk of fractures. In this condition, the decline in estrogen levels that occurs during menopause accelerates bone loss, resulting in a decrease in bone density and quality, which can lead to fragility fractures, particularly in the hips, wrists, and spine.

It's important to note that while postmenopausal osteoporosis is more common in women, men can also develop osteoporosis due to other factors such as aging, lifestyle choices, and medical conditions.

Adrenalectomy is a surgical procedure in which one or both adrenal glands are removed. The adrenal glands are small, triangular-shaped glands located on top of each kidney that produce hormones such as cortisol, aldosterone, and adrenaline (epinephrine).

There are several reasons why an adrenalectomy may be necessary. For example, the procedure may be performed to treat tumors or growths on the adrenal glands, such as pheochromocytomas, which can cause high blood pressure and other symptoms. Adrenalectomy may also be recommended for patients with Cushing's syndrome, a condition in which the body is exposed to too much cortisol, or for those with adrenal cancer.

During an adrenalectomy, the surgeon makes an incision in the abdomen or back and removes the affected gland or glands. In some cases, laparoscopic surgery may be used, which involves making several small incisions and using specialized instruments to remove the gland. After the procedure, patients may need to take hormone replacement therapy to compensate for the loss of adrenal gland function.

Secretory rate refers to the amount or volume of a secretion produced by a gland or an organ over a given period of time. It is a measure of the productivity or activity level of the secreting structure. The secretory rate can be quantified for various bodily fluids, such as saliva, sweat, digestive enzymes, hormones, or milk, depending on the context and the specific gland or organ being studied.

In clinical settings, measuring the secretory rate might involve collecting and analyzing samples over a certain duration to estimate the production rate of the substance in question. This information can be helpful in diagnosing conditions related to impaired secretion, monitoring treatment responses, or understanding the physiological adaptations of the body under different circumstances.

Lagomorpha is an order of mammals that includes rabbits, hares, and pikas. They are herbivores with large incisors in the front of their mouths and a second pair of smaller incisors behind them. Lagomorpha is distinguished from other orders by its unique dental characteristics and the presence of two pairs of upper incisors. These animals are known for their high reproductive rates and are found worldwide, except for Antarctica and some islands.

Stomach volvulus is a medical condition that involves the twisting or rotation of the stomach around its axis, leading to obstruction of the inflow and outflow of the stomach. This can result in strangulation of the blood supply to the stomach wall, potentially causing ischemia, necrosis, and perforation if not promptly treated. It is a surgical emergency that requires immediate medical attention. The condition can be congenital or acquired, with the acquired form being more common and often associated with underlying conditions such as gastric distention, laxity of gastrocolic ligaments, or previous abdominal surgery.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

Osteogenesis is the process of bone formation or development. It involves the differentiation and maturation of osteoblasts, which are bone-forming cells that synthesize and deposit the organic matrix of bone tissue, composed mainly of type I collagen. This organic matrix later mineralizes to form the inorganic crystalline component of bone, primarily hydroxyapatite.

There are two primary types of osteogenesis: intramembranous and endochondral. Intramembranous osteogenesis occurs directly within connective tissue, where mesenchymal stem cells differentiate into osteoblasts and form bone tissue without an intervening cartilage template. This process is responsible for the formation of flat bones like the skull and clavicles.

Endochondral osteogenesis, on the other hand, involves the initial development of a cartilaginous model or template, which is later replaced by bone tissue. This process forms long bones, such as those in the limbs, and occurs through several stages involving chondrocyte proliferation, hypertrophy, and calcification, followed by invasion of blood vessels and osteoblasts to replace the cartilage with bone tissue.

Abnormalities in osteogenesis can lead to various skeletal disorders and diseases, such as osteogenesis imperfecta (brittle bone disease), achondroplasia (a form of dwarfism), and cleidocranial dysplasia (a disorder affecting skull and collarbone development).

"Mesocricetus" is a genus of rodents, more commonly known as hamsters. It includes several species of hamsters that are native to various parts of Europe and Asia. The best-known member of this genus is the Syrian hamster, also known as the golden hamster or Mesocricetus auratus, which is a popular pet due to its small size and relatively easy care. These hamsters are burrowing animals and are typically solitary in the wild.

He mastered ovariectomy. He was exceptionally known for the nephrectomy using the extra-peritoneal route. In 1903, succeeding ... in many works he gave precise documentation of a large personal case series on the subject of hysterectomy and ovariectomy. He ...
On ovariectomy-induced osteoporosis". Upsala Journal of Medical Sciences. 114 (3): 140-8. doi:10.1080/03009730902891784. PMC ...
... and Flank Ovariectomy Using the Same Method for Hemostasis". Animals. 10 (12): 2223. doi:10.3390/ani10122223. PMC 7761362. PMID ... "The effect of splash block on the need for analgesia in dogs subjected to video-assisted ovariectomy". Veterinary Medicine and ... "Comparison of intraoperative and postoperative pain during canine ovariohysterectomy and ovariectomy". The Canadian Veterinary ...
One form of spaying is to remove only the ovaries (oophorectomy or ovariectomy), which is mainly done in cats and young dogs. ... "Effects of bilateral ovariectomy via colpotomy in mares: 23 cases (1984-1990)". Journal of the American Veterinary Medical ...
"Effects of 3-Adrenergic Receptor Activation on Rat Urinary Bladder Hyperactivity Induced by Ovariectomy". Journal of ...
September 2004). "Ovariectomy and 17β-estradiol modulate disease progression of a mouse model of ALS". Brain Research. 1021 (1 ... By conducting treatment of 17β-estradiol to ovariectomy treated mice, scientists found significantly delay of disease ...
... and ovariectomy-induced obesity in mice". J. Biol. Chem. 285 (41): 31292-303. doi:10.1074/jbc.M110.147850. PMC 2951204. PMID ...
2015), the overall maturation rate after IVM of oocytes recovered from ovariectomy specimens in laboratory was 36%. The ... of oocytes recovered from ovariectomy specimens in the laboratory: a promising "ex vivo" method of oocyte cryopreservation ...
... daily injections of coumestrol were shown to reduce bone loss in rats who had undergone an ovariectomy. Coumestrol has been ...
The same year, the first ovariectomy in Boston was carried out in Carney by Henry I. Bowditch. The first Catholic nursing ...
Geusens, Piet; Dequeker, Jan; Nijs, Jos; Bramm, Erik (1990). "Effect of ovariectomy and prednisolone on bone mineral content in ...
2020-07-28). "Ovariectomy uncouples lifespan from metabolic health and reveals a sex-hormone-dependent role of hepatic mTORC2 ...
J. C. Prior et al., "Premenopausal ovariectomy-related bone loss: a randomized, double-blind, one-year trial of conjugated ...
"Experimental osteoporosis induced by ovariectomy and vitamin D deficiency does not markedly affect fracture healing in rats" ( ...
His mother was the first woman to undergo an ovariectomy, in 1809 in Danville, Kentucky to remove a tumor. Crawford was elected ...
This effect can be seen following ovariectomy and hormone replacement as well as under naturally occurring changes in hormone ...
Neutering in animals describes spaying or castration (also please see castration). To spay (medical term: ovariectomy or ovario ... With an ovariectomy ligatures are placed on the blood vessels above and below the ovary and the organ is removed. With an ...
Bowe (November 2006). "The hop phytoestrogen, 8-prenylnaringenin, reverses the ovariectomy-induced rise in skin temperature in ... Bowe, James (November 15, 2012). "The hop phytoestrogen, 8-prenylnaringenin, reverses the ovariectomy-induced rise in skin ...
After ovariectomy (a procedure used to mimic menopause) in female mice, circulating LH levels surge while CNS levels of LH fall ...
Furthermore, some methods such as ovariectomy and altered light-dark cycles have been developed to study the mechanism of ...
Regulate Bone Resorption II Adenosine A1R Blockade or Deletion Increases Bone Density and Prevents Ovariectomy-Induced Bone ...
Concerning hormones, displays of lordosis can be affected by ovariectomy, injections of estradiol benzoate and progesterone, or ...
Women who were menopausal due to ovariectomy showed significantly greater improvement in sexual function with testosterone ...
Decreased estrogen is a common cause of osteoporosis that can be seen in other conditions such as ovariectomy, ovarian failure ...
They established that ovariectomies reduced the incidence of mammary tumors and that tumor susceptibility varied in different ...
EEs are used in hormone therapy for menopausal symptoms, female hypogonadism, ovariectomy, and primary ovarian failure and in ...
The surgery is also called ovariectomy, but this term is mostly used in reference to animals, e.g. the surgical removal of ...
... is a rare condition in an individual has one ovary instead of two not explained by previous ovariectomy. Possible causes ...
... and aromatase inhibitors like anastrozole and ovariectomy.[citation needed] A breast biopsy is tested for whether the cancer ...
In 1837 West published in The Lancet a description of the first ovariectomy, describing how he removed an ovarian cyst with a ... He published in 1837 the first article referred to an ovariectomy performed in England and first described the picture of a ...
Ovariectomy (ovx) results in bone loss associated with altered immune status. The purpose of this study was to determine if ... Ovariectomy Is the Subject Area "Ovariectomy" applicable to this article? Yes. No. ...
Once the veterinarian confirms hormones are to blame, "can we justify ovariectomy on grounds of behavior?" Crabtree. Create a ... Could removing these mares ovaries-via a surgical procedure called an ovariectomy-be a viable solution? James Crabtree, BVM&S ... content: %22While removing mares ovaries-via a surgical procedure called an ovariectomy-can be successful in remedying ...
This also means anesthesia time is shorter with an ovariectomy. Is an ovariectomy less risky?. Complications are rare with both ... What are the limitations of an ovariectomy?. One important limitation of the ovariectomy is that it should only be performed in ... The ovariectomy has been practiced for decades in Europe, among other locations, with reportedly no increase in the numbers of ... Commonly performed in other countries is the ovariectomy, in which only the ovaries are removed, while the uterus is left in ...
Olive oil effectively mitigated ovariectomy-induced osteoporosis in rats, and is a promising candidate for the treatment of ... 4 weeks before ovariectomy and 8 weeks after. At the end of the experiment, blood samples were collected. Plasma levels of ... Our data showed that ovariectomy led to significant hypocalcemia in the OVX-rats. A previous study reported that ovariectomy in ... Saleh, N.K., Saleh, H.A. Olive Oil effectively mitigates ovariectomy-induced osteoporosis in rats. BMC Complement Altern Med 11 ...
Rehnström, M., Ahnstedt, H., Krause, D. N., Edvinsson, M. L., Haanes, K. A., & Edvinsson, L. (2022). Ovariectomy Reduces ... Ovariectomy Reduces Vasocontractile Responses of Rat Middle Cerebral Arteries After Focal Cerebral Ischemia. I: Journal of ... Rehnström, M, Ahnstedt, H, Krause, DN, Edvinsson, ML, Haanes, KA & Edvinsson, L 2022, Ovariectomy Reduces Vasocontractile ... Ovariectomy Reduces Vasocontractile Responses of Rat Middle Cerebral Arteries After Focal Cerebral Ischemia. Journal of ...
Dufonexport is a leading Snook Ovariectomy Hook manufacturer, supplier and exporter in India. ... Snook Ovariectomy Hook, Snook Ovariectomy Hook in India, Snook Ovariectomy Hook Exporter, Snook Ovariectomy Hook School Lab ... Snook Ovariectomy Hook Snook Ovariectomy Hook Manufacturer India and School Lab Snook Ovariectomy Hook Suppliers India. for ... Dufon Snook Ovariectomy Hook are leading Manufacturers India for Lab, Snook Ovariectomy Hook Manufacturer India, Snook ...
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Ovariectomy and estrogen replacement. The aged monkeys received bilateral ovariectomies before neuropsychological testing. ... Cognitive effects of ovariectomy and cyclic estrogen replacement Behavioral testing was initiated 2 d after the second ... In contrast, ovariectomy exacerbated age-related deficits in object discrimination learning; the magnitude of this effect was ... Here we adopted a controlled, prospective design in a nonhuman primate model to test the effects of ovariectomy and estrogen ...
Ovariectomy. 780. 30. The utilization of texturized P (VDF-TrFE)/BT, regardless of the association with photobiomodulation ...
BACKGROUND AND PURPOSE: Ovariectomy accelerates age-related skin changes as adequate oestrogen levels are required to control ... Genistein aglycone, a soy-derived isoflavone, improves skin changes induced by ovariectomy in rats. POLITO, FRANCESCA;MARINI, ... BACKGROUND AND PURPOSE: Ovariectomy accelerates age-related skin changes as adequate oestrogen levels are required to control ... EXPERIMENTAL APPROACH: Six months after ovariectomy, rats were randomly allocated to different groups and treated, daily, with ...
He mastered ovariectomy. He was exceptionally known for the nephrectomy using the extra-peritoneal route. In 1903, succeeding ... in many works he gave precise documentation of a large personal case series on the subject of hysterectomy and ovariectomy. He ...
MILHAN, Noala Vicensoto Moreira et al. Influence of ovariectomy combined with lack of masticatory force in the evolution of ... Aim: To evaluate the influence of ovariectomy combined with lack of masticatory force in the evolution of periodontal disease ... Methods: Forty rats were bilaterally ovariectomized and 40 were submitted to sham ovariectomy. Periodontal disease was induced ...
... ... "Protective effects of Vitex agnus-castus in ovariectomy mice following permanent middle cerebral artery occlusion". Iranian ... Protective effects of Vitex agnus-castus in ovariectomy mice following permanent middle cerebral artery occlusion. Iranian ... Protective effects of Vitex agnus-castus in ovariectomy mice following permanent middle cerebral artery occlusion, Iranian ...
Can Equine Ovariectomies Be Justified on Behavioral Grounds? Alexandra Beckstett, The Horse Managing Editor March 16, 2018 ...
Mesenchymal stem tissues avoid ovariectomy-induced weakening of bones enhancement inside mice via intraosseous vascular ...
Aging impairs galanin expression in luteinizing hormone-releasing hormone neurons: effect of ovariectomy and /or estradiol ... Aging impairs galanin expression in luteinizing hormone-releasing hormone neurons: effect of ovariectomy and /or estradiol ... Aging impairs galanin expression in luteinizing hormone-releasing hormone neurons: effect of ovariectomy and /or estradiol ...
A PCR Analysis of ERα and ERβ mRNA Abundance in Rats and the Effect of Ovariectomy, doi: 10.1359/jbmr.1999.14.7.1189, category ... After ovariectomy, the expression of ERalpha mRNA decreased abruptly in the bone marrow and renal cortex, and both ERalpha and ... YUHSpace: A PCR Analysis of ERα and ERβ mRNA Abundance in Rats and the Effect of Ovariectomy. menu ... The mRNA expression of ERalpha in the bone marrow and renal cortex decreased abruptly after ovariectomy, which may partially ...
In rats with ovariectomy-induced depressive-like behavior, showed parallelly elevated IL-6 and IDO protein levels in the ...
Relationship between cancellous bone induced magnetic field and ultrastructure in a rat ovariectomy model. Magnetic Resonance ... Relationship between cancellous bone induced magnetic field and ultrastructure in a rat ovariectomy model. In: Magnetic ... Relationship between cancellous bone induced magnetic field and ultrastructure in a rat ovariectomy model. / Takahashi, Masaya ... keywords = "NMR microscopy, Osteoporosis, Ovariectomy, Phase map, Trabecular bone",. author = "Masaya Takahashi and Wehrli, { ...
Ovariectomy and obesity have equal impact in causing mitochondrial dysfunction and impaired skeletal muscle contraction in rats ... muscle dysfunction may occur due to increased muscle oxidative stress and mitochondrial dysfunction as a result of ovariectomy ...
Murine Orchiectomy and Ovariectomy to Reduce Sex Hormone Production. Authors Author. Ashley A. Rowe1, Yacine Issioui1, Blessing ...
Ovariectomy / adverse effects* * Ovariectomy / statistics & numerical data * Parkinsonian Disorders / epidemiology * ...
Effects of ovariectomy on turnover of alveolar bone in the healed extraction socket in rat edentulous mandible. / Shoji, Kanako ... Effects of ovariectomy on turnover of alveolar bone in the healed extraction socket in rat edentulous mandible. Archives of ... Shoji, K., Elsubeihi, E. S., & Heersche, J. N. M. (2011). Effects of ovariectomy on turnover of alveolar bone in the healed ... title = "Effects of ovariectomy on turnover of alveolar bone in the healed extraction socket in rat edentulous mandible", ...
Additional Keywords : Ovariectomy-Induced Changes. [+] In utero exposure to germinated brown rice and its GABA extract ...
Title: Alpha-1 antitrypsin reduces ovariectomy-induced bone loss in mice Author. Cao, Jay ... We found that ovariectomy decreased wet uterus weight, caused significant bone loss, and increased serum leptin concentrations ... Alpha-1 antitrypsin reduces ovariectomy-induced bone loss in mice. Annals of the New York Academy of Sciences. doi: 10.111/j. ... We conclude that AAT mitigates ovariectomy-induced bone loss in mice possibly through inhibiting osteoclast activity and bone ...
1 Snook Ovariectomy Hook *2 Kelly Forceps, Curved *1 Metzenbaum Scissors, Curved ...
Platinum nanoparticle reduces ovariectomy-induced bone loss by decreasing osteoclastogenesis. Kim W. , Kim J. , Kim J. , Choi H ... Intragastrical administration of platinum nanoparticle reduced ovariectomy (OVX)-induced bone loss with lowered level of in ...
  • Other Related Teaching Lab Products, Scientific Instruments and Educational Equipments like Snook Ovariectomy Hook. (dufonexport.com)
  • We conclude that AAT mitigates ovariectomy-induced bone loss in mice possibly through inhibiting osteoclast activity and bone resorption and AAT can be a potential agent to prevent bone loss in humans. (usda.gov)
  • Olive oil effectively mitigated ovariectomy-induced osteoporosis in rats, and is a promising candidate for the treatment of postmenopausal osteoporosis. (biomedcentral.com)
  • After ovariectomy, the expression of ERalpha mRNA decreased abruptly in the bone marrow and renal cortex, and both ERalpha and ERbeta were barely detected in the trabecular bone. (yonsei.ac.kr)
  • The mRNA expression of ERalpha in the bone marrow and renal cortex decreased abruptly after ovariectomy, which may partially explain why the effect of estrogen deficiency can be amplified and why trabecular bone loss is more predominant than cortical bone loss shortly after surgical or natural menopause. (yonsei.ac.kr)
  • Since osseointegration around implants requires formation and maintenance of new bone, knowledge of how ovariectomy (OVX) affects turnover of mandibular and maxillary bone is required. (elsevierpure.com)
  • Results: Bone turnover was increased by ovariectomy (OVX) as reflected by increased static parameters of bone formation and resorption. (elsevierpure.com)
  • Heersche, Johan N.M. / Effects of ovariectomy on turnover of alveolar bone in the healed extraction socket in rat edentulous mandible . (elsevierpure.com)
  • The site-dependent variations in trabecular bone morphology were studied in the rat tibia by magnitude and phase difference three-dimensional nuclear magnetic resonance microscopy and image processing, and the implications of ovariectomy were evaluated. (elsevierpure.com)
  • We found that ovariectomy decreased wet uterus weight, caused significant bone loss, and increased serum leptin concentrations in mice compared to sham. (usda.gov)
  • The classical three-point bending and impact tests were carried out for three rat bone groups: control (SHO), the humerus of animals under the conditions of established osteopenia (OVX), and bones of rats receiving nesfatin-1 after ovariectomy (NES). (mdpi.com)
  • Intragastrical administration of platinum nanoparticle reduced ovariectomy (OVX)-induced bone loss with lowered level of in vivo bone resorption. (endocrine-abstracts.org)
  • Mesenchymal stem tissues avoid ovariectomy-induced weakening of bones enhancement inside mice via intraosseous vascular redecorating. (aktinhibitor.com)
  • Non-childbearing potential is defined as current bilateral tubal ligation or occlusion, hysterectomy, bilateral ovariectomy or post-menopause. (who.int)
  • Under such background, we have supplemented Ovariectomized (OVX) - rats with olive oil four weeks before ovariectomy with an aim to evaluate the efficacy of olive oil supplementation starting before menopause. (biomedcentral.com)
  • Aim: To evaluate the influence of ovariectomy combined with lack of masticatory force in the evolution of periodontal disease induced in rats. (bvsalud.org)
  • Methods: Forty rats were bilaterally ovariectomized and 40 were submitted to sham ovariectomy. (bvsalud.org)
  • Ketanserin and anxiety levels: Influence of gender, estrous cycle, ovariectomy and ovarian hormones in female rats. (bvsalud.org)
  • The article goes on to describe how an ovariectomy is (logically) less invasive and faster than an ovariohysterectomy 1 . (pethealthnetwork.com)
  • Ovariohysterectomy or ovariectomy can be performed using laparoscopy in most all medium and large size dogs. (vin.com)
  • content: %22While removing mares' ovaries-via a surgical procedure called an ovariectomy-can be successful in remedying aggressive behavior, other estrous behavior can persist even following surgery. (thehorse.com)
  • Could removing these mares' ovaries-via a surgical procedure called an ovariectomy-be a viable solution? (thehorse.com)
  • Commonly performed in other countries is the ovariectomy, in which only the ovaries are removed, while the uterus is left in the belly. (pethealthnetwork.com)
  • Here we adopted a controlled, prospective design in a nonhuman primate model to test the effects of ovariectomy and estrogen replacement on normal cognitive aging. (jneurosci.org)
  • To study the relative abundance and the changes of both estrogen receptor alpha (ERalpha) and ERbeta mRNA before and after ovariectomy in major organs important to the regulation of calcium homeostasis, we compared the degree of mRNA expression of ERalpha to that of ERbeta in rat tissues by performing competitive reverse transcription polymerase chain reaction (RT-PCR) with internal standards. (yonsei.ac.kr)
  • The ovariectomy has been practiced for decades in Europe, among other locations, with reportedly no increase in the numbers of patients with future diseases of the uterus. (pethealthnetwork.com)
  • One important limitation of the ovariectomy is that it should only be performed in young, healthy females with a healthy uterus. (pethealthnetwork.com)
  • Female former entiate between hysterectomies with and exposure may be increased during phases of workers at the Bunker Hill smelter in Idaho without ovariectomies. (cdc.gov)
  • Is the Subject Area "Ovariectomy" applicable to this article? (plos.org)