Luteinizing Hormone: 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.Receptors, LH: Those protein complexes or molecular sites on the surfaces and cytoplasm of gonadal cells that bind luteinizing or chorionic gonadotropic hormones and thereby cause the gonadal cells to synthesize and secrete sex steroids. The hormone-receptor complex is internalized from the plasma membrane and initiates steroid synthesis.Gonadotropin-Releasing Hormone: 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.Ovulation: The discharge of an OVUM from a rupturing follicle in the OVARY.Proestrus: A phase of the ESTROUS CYCLE that precedes ESTRUS. During proestrus, the Graafian follicles undergo maturation.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.Follicle Stimulating Hormone: 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.Estrus: The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.Estradiol: 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.Follicular Phase: The period of the MENSTRUAL CYCLE representing follicular growth, increase in ovarian estrogen (ESTROGENS) production, and epithelial proliferation of the ENDOMETRIUM. Follicular phase begins with the onset of MENSTRUATION and ends with OVULATION.Ovariectomy: The surgical removal of one or both ovaries.Ovarian Follicle: 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.Pituitary Gland: A small, unpaired gland situated in the SELLA TURCICA. It is connected to the HYPOTHALAMUS by a short stalk which is called the INFUNDIBULUM.Ovary: 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.Gonadotropins, Pituitary: 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).Prolactin: 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.Sheep: 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.Preoptic Area: Region of hypothalamus between the ANTERIOR COMMISSURE and OPTIC CHIASM.Secretory Rate: 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.Sexual Maturation: Achievement of full sexual capacity in animals and in humans.Chorionic Gonadotropin: A gonadotropic glycoprotein hormone produced primarily by the PLACENTA. Similar to the pituitary LUTEINIZING HORMONE in structure and function, chorionic gonadotropin is involved in maintaining the CORPUS LUTEUM during pregnancy. CG consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is virtually identical to the alpha subunits of the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity (CHORIONIC GONADOTROPIN, BETA SUBUNIT, HUMAN).Estrous Cycle: 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).Pituitary Hormone-Releasing Hormones: 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.Castration: Surgical removal or artificial destruction of gonads.Diestrus: A phase of the ESTROUS CYCLES that follows METESTRUS. Diestrus is a period of sexual quiescence separating phases of ESTRUS in polyestrous animals.Luteal Phase: The period in the MENSTRUAL CYCLE that follows OVULATION, characterized by the development of CORPUS LUTEUM, increase in PROGESTERONE production by the OVARY and secretion by the glandular epithelium of the ENDOMETRIUM. The luteal phase begins with ovulation and ends with the onset of MENSTRUATION.Kisspeptins: Intercellular signaling peptides that were originally characterized by their ability to suppress NEOPLASM METASTASIS. Kisspeptins have since been found to play an important role in the neuroendocrine regulation of REPRODUCTION.Hypothalamus: Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.Circadian Rhythm: The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.Inhibins: 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, respectivelyHormone Antagonists: Chemical substances which inhibit the function of the endocrine glands, the biosynthesis of their secreted hormones, or the action of hormones upon their specific sites.Testosterone: 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.Gonadotropins, Equine: Gonadotropins secreted by the pituitary or the placenta in horses. This term generally refers to the gonadotropins found in the pregnant mare serum, a rich source of equine CHORIONIC GONADOTROPIN; LUTEINIZING HORMONE; and FOLLICLE STIMULATING HORMONE. Unlike that in humans, the equine LUTEINIZING HORMONE, BETA SUBUNIT is identical to the equine choronic gonadotropin, beta. Equine gonadotropins prepared from pregnant mare serum are used in reproductive studies.Ovulation Detection: Method to determine the occurrence of OVULATION by direct or indirect means. Indirect methods examine the effects of PROGESTERONE on cervical mucus (CERVIX MUCUS), or basal body temperature. Direct ovulation detection, generally used in fertility treatment, involves analyses of circulating hormones in blood and ULTRASONOGRAPHY.Radioimmunoassay: Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.Follicular Fluid: The fluid surrounding the OVUM and GRANULOSA CELLS in the Graafian follicle (OVARIAN FOLLICLE). The follicular fluid contains sex steroids, glycoprotein hormones, plasma proteins, mucopolysaccharides, and enzymes.Median Eminence: Raised area at the infundibular region of the HYPOTHALAMUS at the floor of the BRAIN, ventral to the THIRD VENTRICLE and adjacent to the ARCUATE NUCLEUS OF HYPOTHALAMUS. It contains the terminals of hypothalamic neurons and the capillary network of hypophyseal portal system, thus serving as a neuroendocrine link between the brain and the PITUITARY GLAND.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Anestrus: A state of sexual inactivity in female animals exhibiting no ESTROUS CYCLE. Causes of anestrus include pregnancy, presence of offspring, season, stress, and pathology.Pituitary Gland, Anterior: The anterior glandular lobe of the pituitary gland, also known as the adenohypophysis. It secretes the ADENOHYPOPHYSEAL HORMONES that regulate vital functions such as GROWTH; METABOLISM; and REPRODUCTION.Ovulation Induction: Techniques for the artifical induction of ovulation, the rupture of the follicle and release of the ovum.Drug Implants: Small containers or pellets of a solid drug implanted in the body to achieve sustained release of the drug.Granulosa Cells: Supporting cells for the developing female gamete in the OVARY. They are derived from the coelomic epithelial cells of the gonadal ridge. Granulosa cells form a single layer around the OOCYTE in the primordial ovarian follicle and advance to form a multilayered cumulus oophorus surrounding the OVUM in the Graafian follicle. The major functions of granulosa cells include the production of steroids and LH receptors (RECEPTORS, LH).Feedback: 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.Luteinization: Formation of CORPUS LUTEUM. This process includes capillary invasion of the ruptured OVARIAN FOLLICLE, hypertrophy of the GRANULOSA CELLS and the THECA CELLS, and the production of PROGESTERONE. Luteinization is regulated by LUTEINIZING HORMONE.Copulation: Sexual union of a male and a female in non-human species.Methallibure: A dithiobiurea compound with anti-gonadotropic activity.Menstrual Cycle: The period from onset of one menstrual bleeding (MENSTRUATION) to the next in an ovulating woman or female primate. The menstrual cycle is regulated by endocrine interactions of the HYPOTHALAMUS; the PITUITARY GLAND; the ovaries; and the genital tract. The menstrual cycle is divided by OVULATION into two phases. Based on the endocrine status of the OVARY, there is a FOLLICULAR PHASE and a LUTEAL PHASE. Based on the response in the ENDOMETRIUM, the menstrual cycle is divided into a proliferative and a secretory phase.Gonadotropins: Hormones that stimulate gonadal functions such as GAMETOGENESIS and sex steroid hormone production in the OVARY and the TESTIS. Major gonadotropins are glycoproteins produced primarily by the adenohypophysis (GONADOTROPINS, PITUITARY) and the placenta (CHORIONIC GONADOTROPIN). In some species, pituitary PROLACTIN and PLACENTAL LACTOGEN exert some luteotropic activities.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Receptors, LHRH: Receptors with a 6-kDa protein on the surfaces of cells that secrete LUTEINIZING HORMONE or FOLLICLE STIMULATING HORMONE, usually in the adenohypophysis. LUTEINIZING HORMONE-RELEASING HORMONE binds to these receptors, is endocytosed with the receptor and, in the cell, triggers the release of LUTEINIZING HORMONE or FOLLICLE STIMULATING HORMONE by the cell. These receptors are also found in rat gonads. INHIBINS prevent the binding of GnRH to its receptors.Superovulation: Occurrence or induction of release of more ova than are normally released at the same time in a given species. The term applies to both animals and humans.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Pseudopregnancy: 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.Hypothalamus, Middle: Middle portion of the hypothalamus containing the arcuate, dorsomedial, ventromedial nuclei, the TUBER CINEREUM and the PITUITARY GLAND.Bromocriptine: A semisynthetic ergotamine alkaloid that is a dopamine D2 agonist. It suppresses prolactin secretion.Theca Cells: The flattened stroma cells forming a sheath or theca outside the basal lamina lining the mature OVARIAN FOLLICLE. Thecal interstitial or stromal cells are steroidogenic, and produce primarily ANDROGENS which serve as precusors of ESTROGENS in the GRANULOSA CELLS.Estrus Synchronization: Occurrence or induction of ESTRUS in all of the females in a group at the same time, applies only to non-primate mammals with ESTROUS CYCLE.Androstenedione: A delta-4 C19 steroid that is produced not only in the TESTIS, but also in the OVARY and the ADRENAL CORTEX. Depending on the tissue type, androstenedione can serve as a precursor to TESTOSTERONE as well as ESTRONE and ESTRADIOL.Feedback, Physiological: A mechanism of communication with a physiological system for homeostasis, adaptation, etc. Physiological feedback is mediated through extensive feedback mechanisms that use physiological cues as feedback loop signals to control other systems.Dinoprost: A naturally occurring prostaglandin that has oxytocic, luteolytic, and abortifacient activities. Due to its vasocontractile properties, the compound has a variety of other biological actions.Gonadal Steroid Hormones: 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.Anterior Thalamic Nuclei: Three nuclei located beneath the dorsal surface of the most rostral part of the thalamus. The group includes the anterodorsal nucleus, anteromedial nucleus, and anteroventral nucleus. All receive connections from the MAMILLARY BODY and BRAIN FORNIX, and project fibers to the CINGULATE BODY.Sexual Behavior, Animal: Sexual activities of animals.Estrogens: 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.Mifepristone: A progestational and glucocorticoid hormone antagonist. Its inhibition of progesterone induces bleeding during the luteal phase and in early pregnancy by releasing endogenous prostaglandins from the endometrium or decidua. As a glucocorticoid receptor antagonist, the drug has been used to treat hypercortisolism in patients with nonpituitary CUSHING SYNDROME.Anovulation: Suspension or cessation of OVULATION in animals or humans with follicle-containing ovaries (OVARIAN FOLLICLE). Depending on the etiology, OVULATION may be induced with appropriate therapy.Rats, Inbred Strains: 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.Oviposition: The process of laying or shedding fully developed eggs (OVA) from the female body. The term is usually used for certain INSECTS or FISHES with an organ called ovipositor where eggs are stored or deposited before expulsion from the body.Follicle Stimulating Hormone, beta Subunit: The beta subunit of follicle stimulating hormone. It is a 15-kDa glycopolypeptide. Full biological activity of FSH requires the non-covalently bound heterodimers of an alpha and a beta subunit. Mutation of the FSHB gene causes delayed puberty, or infertility.Fertility Agents: Drugs used to increase fertility or to treat infertility.Orchiectomy: The surgical removal of one or both testicles.Hypothalamo-Hypophyseal System: A collection of NEURONS, tracts of NERVE FIBERS, endocrine tissue, and blood vessels in the HYPOTHALAMUS and the PITUITARY GLAND. This hypothalamo-hypophyseal portal circulation provides the mechanism for hypothalamic neuroendocrine (HYPOTHALAMIC HORMONES) regulation of pituitary function and the release of various PITUITARY HORMONES into the systemic circulation to maintain HOMEOSTASIS.Dimethyldithiocarbamate: A chemical that acts as a dopamine beta-hydroxylase inhibitor. Its salts are agricultural fungicides. It is inferior to diethyldithiocarbamate as a chelating agent.Oxytocin: A nonapeptide hormone released from the neurohypophysis (PITUITARY GLAND, POSTERIOR). It differs from VASOPRESSIN by two amino acids at residues 3 and 8. Oxytocin acts on SMOOTH MUSCLE CELLS, such as causing UTERINE CONTRACTIONS and MILK EJECTION.Luteolytic Agents: Chemical compounds causing LUTEOLYSIS or degeneration.Hormones: Chemical substances having a specific regulatory effect on the activity of a certain organ or organs. The term was originally applied to substances secreted by various ENDOCRINE GLANDS and transported in the bloodstream to the target organs. It is sometimes extended to include those substances that are not produced by the endocrine glands but that have similar effects.Cloprostenol: A synthetic prostaglandin F2alpha analog. The compound has luteolytic effects and is used for the synchronization of estrus in cattle.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Neurosecretory Systems: A system of NEURONS that has the specialized function to produce and secrete HORMONES, and that constitutes, in whole or in part, an ENDOCRINE SYSTEM or organ.Pituitary Gland, Intermediate: The intermediate lobe of the pituitary gland. It shows considerable size variation among the species, small in humans, and large in amphibians and lower vertebrates. This lobe produces mainly MELANOCYTE-STIMULATING HORMONES and other peptides from post-translational processing of pro-opiomelanocortin (POMC).Luteinizing Hormone, beta Subunit: The beta subunit of luteinizing hormone. It is a 15-kDa glycopolypeptide with structure similar to the beta subunit of the placental chorionic gonadatropin (CHORIONIC GONADOTROPIN, BETA SUBUNIT, HUMAN) except for the additional 31 amino acids at the C-terminal of CG-beta. Full biological activity of LH requires the non-covalently bound heterodimers of an alpha and a beta subunit. Mutation of the LHB gene causes HYPOGONADISM and infertility.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Mesocricetus: 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.Fertility Agents, Female: Compounds which increase the capacity to conceive in females.Postpartum Period: In females, the period that is shortly after giving birth (PARTURITION).Anterior Hypothalamic Nucleus: Loose heterogeneous collection of cells in the anterior hypothalamus, continuous rostrally with the medial and lateral PREOPTIC AREAS and caudally with the TUBER CINEREUM.Metestrus: The period following ESTRUS during which the phenomena of estrus subside in those animals in which pregnancy or pseudopregnancy does not occur.Periodicity: The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).Insemination, Artificial: Artificial introduction of SEMEN or SPERMATOZOA into the VAGINA to facilitate FERTILIZATION.RNA, Messenger: 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.Ornipressin: A synthetic analog of vasopressin with ORNITHINE substitution at residue 8 of the cyclic nonapeptide. It is used as a local vasoconstrictor and hemostatic.Follicular Atresia: The degeneration and resorption of an OVARIAN FOLLICLE before it reaches maturity and ruptures.Testis: The male gonad containing two functional parts: the SEMINIFEROUS TUBULES for the production and transport of male germ cells (SPERMATOGENESIS) and the interstitial compartment containing LEYDIG CELLS that produce ANDROGENS.Rats, Sprague-Dawley: 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.Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Cyclonic Storms: Non-frontal low-pressure systems over tropical or sub-tropical waters with organized convection and definite pattern of surface wind circulation.Triptorelin Pamoate: A potent synthetic long-acting agonist of GONADOTROPIN-RELEASING HORMONE with D-tryptophan substitution at residue 6.Naloxone: A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.Gonadotrophs: Anterior pituitary cells that can produce both FOLLICLE STIMULATING HORMONE and LUTEINIZING HORMONE.Depression, Chemical: The decrease in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.Atrazine: A selective triazine herbicide. Inhalation hazard is low and there are no apparent skin manifestations or other toxicity in humans. Acutely poisoned sheep and cattle may show muscular spasms, fasciculations, stiff gait, increased respiratory rates, adrenal degeneration, and congestion of the lungs, liver, and kidneys. (From The Merck Index, 11th ed)Progesterone Congeners: Steroidal compounds related to PROGESTERONE, the major mammalian progestational hormone. Progesterone congeners include important progesterone precursors in the biosynthetic pathways, metabolites, derivatives, and synthetic steroids with progestational activities.Follicular Cyst: Cyst due to the occlusion of the duct of a follicle or small gland.Proto-Oncogene Proteins c-fos: Cellular DNA-binding proteins encoded by the c-fos genes (GENES, FOS). They are involved in growth-related transcriptional control. c-fos combines with c-jun (PROTO-ONCOGENE PROTEINS C-JUN) to form a c-fos/c-jun heterodimer (TRANSCRIPTION FACTOR AP-1) that binds to the TRE (TPA-responsive element) in promoters of certain genes.Pregnancy, Animal: The process of bearing developing young (EMBRYOS or FETUSES) in utero in non-human mammals, beginning from FERTILIZATION to BIRTH.Lactation: The processes of milk secretion by the maternal MAMMARY GLANDS after PARTURITION. The proliferation of the mammary glandular tissue, milk synthesis, and milk expulsion or let down are regulated by the interactions of several hormones including ESTRADIOL; PROGESTERONE; PROLACTIN; and OXYTOCIN.Fertilization in Vitro: An assisted reproductive technique that includes the direct handling and manipulation of oocytes and sperm to achieve fertilization in vitro.Corpus Luteum: The yellow body derived from the ruptured OVARIAN FOLLICLE after OVULATION. The process of corpus luteum formation, LUTEINIZATION, is regulated by LUTEINIZING HORMONE.Prolactin-Releasing Hormone: A hypothalamic hormone that is synthesized as a precursor protein which is cleaved into two peptides. In addition to stimulating PROLACTIN release the peptides bind to specific G-PROTEIN-COUPLED RECEPTORS found at locations within the BRAIN.Oocytes: Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).Disaster Planning: Procedures outlined for the care of casualties and the maintenance of services in disasters.Hydrocortisone: The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.20-alpha-Dihydroprogesterone: A biologically active 20-alpha-reduced metabolite of PROGESTERONE. It is converted from progesterone to 20-alpha-hydroxypregn-4-en-3-one by the 20-ALPHA-HYDROXYSTEROID DEHYDROGENASE in the CORPUS LUTEUM and the PLACENTA.Oncogene Proteins v-fos: Transforming proteins coded by fos oncogenes. These proteins have been found in the Finkel-Biskis-Jinkins (FBJ-MSV) and Finkel-Biskis-Reilly (FBR-MSV) murine sarcoma viruses which induce osteogenic sarcomas in mice. The FBJ-MSV v-fos gene encodes a p55-kDa protein and the FBR-MSV v-fos gene encodes a p75-kDa fusion protein.Arcuate Nucleus: A nucleus located in the middle hypothalamus in the most ventral part of the third ventricle near the entrance of the infundibular recess. Its small cells are in close contact with the ependyma.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Surge Capacity: A health care system's ability to rapidly mobilize to meet an increased demand, to rapidly expand beyond normal services levels to meet the increased demand in the event of large-scale DISASTERS or public health emergencies.Pregnanediol: An inactive metabolite of PROGESTERONE by reduction at C5, C3, and C20 position. Pregnanediol has two hydroxyl groups, at 3-alpha and 20-alpha. It is detectable in URINE after OVULATION and is found in great quantities in the pregnancy urine.Endocrine Glands: Ductless glands that secrete HORMONES directly into the BLOOD CIRCULATION. These hormones influence the METABOLISM and other functions of cells in the body.Nitromifene: A non-steroidal estrogen antagonist (as the 1:1 citrate) most commonly used as a research tool in animal studies.Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Suprachiasmatic Nucleus: An ovoid densely packed collection of small cells of the anterior hypothalamus lying close to the midline in a shallow impression of the OPTIC CHIASM.Infertility, Female: Diminished or absent ability of a female to achieve conception.Follicle Stimulating Hormone, Human: A major gonadotropin secreted by the human adenohypophysis (PITUITARY GLAND, ANTERIOR). Follicle-stimulating hormone stimulates GAMETOGENESIS and the supporting cells such as the ovarian GRANULOSA CELLS, the testicular SERTOLI CELLS, and the LEYDIG CELLS. FSH consists of two noncovalently linked subunits, alpha and beta. The alpha subunit is common in the three human pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Pulsatile Flow: Rhythmic, intermittent propagation of a fluid through a BLOOD VESSEL or piping system, in contrast to constant, smooth propagation, which produces laminar flow.Deer: The family Cervidae of 17 genera and 45 species occurring nearly throughout North America, South America, and Eurasia, on most associated continental islands, and in northern Africa. Wild populations of deer have been established through introduction by people in Cuba, New Guinea, Australia, New Zealand, and other places where the family does not naturally occur. They are slim, long-legged and best characterized by the presence of antlers. Their habitat is forests, swamps, brush country, deserts, and arctic tundra. They are usually good swimmers; some migrate seasonally. (Walker's Mammals of the World, 5th ed, p1362)Turkeys: Large woodland game BIRDS in the subfamily Meleagridinae, family Phasianidae, order GALLIFORMES. Formerly they were considered a distinct family, Melegrididae.Menotropins: Extracts of urine from menopausal women that contain high concentrations of pituitary gonadotropins, FOLLICLE STIMULATING HORMONE and LUTEINIZING HORMONE. Menotropins are used to treat infertility. The FSH:LH ratio and degree of purity vary in different preparations.Pentobarbital: A short-acting barbiturate that is effective as a sedative and hypnotic (but not as an anti-anxiety) agent and is usually given orally. It is prescribed more frequently for sleep induction than for sedation but, like similar agents, may lose its effectiveness by the second week of continued administration. (From AMA Drug Evaluations Annual, 1994, p236)Menstruation: The periodic shedding of the ENDOMETRIUM and associated menstrual bleeding in the MENSTRUAL CYCLE of humans and primates. Menstruation is due to the decline in circulating PROGESTERONE, and occurs at the late LUTEAL PHASE when LUTEOLYSIS of the CORPUS LUTEUM takes place.Freemartinism: A condition occurring in the female offspring of dizygotic twins (TWIN, DIZYGOTIC) in a mixed-sex pregnancy, usually in CATTLE. Freemartinism can occur in other mammals. When placental fusion between the male and the female FETUSES permits the exchange of fetal cells and fetal hormones, TESTICULAR HORMONES from the male fetus can androgenize the female fetus producing a sterile XX/XY chimeric "female"(CHIMERISM).Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Contraceptives, Postcoital, Synthetic: Postcoital contraceptives which owe their effectiveness to synthetic preparations.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Horses: Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.Androgens: Compounds that interact with ANDROGEN RECEPTORS in target tissues to bring about the effects similar to those of TESTOSTERONE. Depending on the target tissues, androgenic effects can be on SEX DIFFERENTIATION; male reproductive organs, SPERMATOGENESIS; secondary male SEX CHARACTERISTICS; LIBIDO; development of muscle mass, strength, and power.Sexual Development: The processes of anatomical and physiological changes related to sexual or reproductive functions during the life span of a human or an animal, from FERTILIZATION to DEATH. These include SEX DETERMINATION PROCESSES; SEX DIFFERENTIATION; SEXUAL MATURATION; and changes during AGING.Prostaglandins F: (9 alpha,11 alpha,13E,15S)-9,11,15-Trihydroxyprost-13-en-1-oic acid (PGF(1 alpha)); (5Z,9 alpha,11,alpha,13E,15S)-9,11,15-trihydroxyprosta-5,13-dien-1-oic acid (PGF(2 alpha)); (5Z,9 alpha,11 alpha,13E,15S,17Z)-9,11,15-trihydroxyprosta-5,13,17-trien-1-oic acid (PGF(3 alpha)). A family of prostaglandins that includes three of the six naturally occurring prostaglandins. All naturally occurring PGF have an alpha configuration at the 9-carbon position. They stimulate uterine and bronchial smooth muscle and are often used as oxytocics.Blood Pressure Monitoring, Ambulatory: Method in which repeated blood pressure readings are made while the patient undergoes normal daily activities. It allows quantitative analysis of the high blood pressure load over time, can help distinguish between types of HYPERTENSION, and can assess the effectiveness of antihypertensive therapy.Uterus: 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.Luteal Cells: PROGESTERONE-producing cells in the CORPUS LUTEUM. The large luteal cells derive from the GRANULOSA CELLS. The small luteal cells derive from the THECA CELLS.Fluoroimmunoassay: The use of fluorescence spectrometry to obtain quantitative results for the FLUORESCENT ANTIBODY TECHNIQUE. One advantage over the other methods (e.g., radioimmunoassay) is its extreme sensitivity, with a detection limit on the order of tenths of microgram/liter.Organ Size: The measurement of an organ in volume, mass, or heaviness.Cumulus Cells: The granulosa cells of the cumulus oophorus which surround the OVUM in the GRAAFIAN FOLLICLE. At OVULATION they are extruded with OVUM.Estrone: An aromatized C18 steroid with a 3-hydroxyl group and a 17-ketone, a major mammalian estrogen. It is converted from ANDROSTENEDIONE directly, or from TESTOSTERONE via ESTRADIOL. In humans, it is produced primarily by the cyclic ovaries, PLACENTA, and the ADIPOSE TISSUE of men and postmenopausal women.Elephants: Large mammals in the family Elephantidae, with columnar limbs, bulky bodies, and elongated snouts. They are the only surviving members of the PROBOSCIDEA MAMMALS.Cold Climate: A climate characterized by COLD TEMPERATURE for a majority of the time during the year.Progestins: Compounds that interact with PROGESTERONE RECEPTORS in target tissues to bring about the effects similar to those of PROGESTERONE. Primary actions of progestins, including natural and synthetic steroids, are on the UTERUS and the MAMMARY GLAND in preparation for and in maintenance of PREGNANCY.Injections, Intraventricular: Injections into the cerebral ventricles.Biological Assay: A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.Ovarian Cysts: General term for CYSTS and cystic diseases of the OVARY.Polycystic Ovary Syndrome: A complex disorder characterized by infertility, HIRSUTISM; OBESITY; and various menstrual disturbances such as OLIGOMENORRHEA; AMENORRHEA; ANOVULATION. Polycystic ovary syndrome is usually associated with bilateral enlarged ovaries studded with atretic follicles, not with cysts. The term, polycystic ovary, is misleading.Disaster Medicine: Branch of medicine involved with management and organization of public health response to disasters and major events including the special health and medical needs of a community in a disaster.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Receptors, Progesterone: Specific proteins found in or on cells of progesterone target tissues that specifically combine with progesterone. The cytosol progesterone-receptor complex then associates with the nucleic acids to initiate protein synthesis. There are two kinds of progesterone receptors, A and B. Both are induced by estrogen and have short half-lives.Flutamide: An antiandrogen with about the same potency as cyproterone in rodent and canine species.Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase: A mixed-function oxygenase that catalyzes the hydroxylation of peptidyllysine, usually in protocollagen, to peptidylhydroxylysine. The enzyme utilizes molecular oxygen with concomitant oxidative decarboxylation of the cosubstrate 2-oxoglutarate to succinate. EC 1.14.11.4.Clomiphene: A triphenyl ethylene stilbene derivative which is an estrogen agonist or antagonist depending on the target tissue. Note that ENCLOMIPHENE and ZUCLOMIPHENE are the (E) and (Z) isomers of Clomiphene respectively.Lactotrophs: Anterior pituitary cells that produce PROLACTIN.Injections, Intramuscular: Forceful administration into a muscle of liquid medication, nutrient, or other fluid through a hollow needle piercing the muscle and any tissue covering it.Dihydrotestosterone: A potent androgenic metabolite of TESTOSTERONE. It is produced by the action of the enzyme 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Stimulation, Chemical: The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.Leuprolide: A potent synthetic long-acting agonist of GONADOTROPIN-RELEASING HORMONE that regulates the synthesis and release of pituitary gonadotropins, LUTEINIZING HORMONE and FOLLICLE STIMULATING HORMONE.Melatonin: A biogenic amine that is found in animals and plants. In mammals, melatonin is produced by the PINEAL GLAND. Its secretion increases in darkness and decreases during exposure to light. Melatonin is implicated in the regulation of SLEEP, mood, and REPRODUCTION. Melatonin is also an effective antioxidant.Hypothalamic Area, Lateral: Area in the hypothalamus bounded medially by the mammillothalamic tract and the anterior column of the FORNIX (BRAIN). The medial edge of the INTERNAL CAPSULE and the subthalamic region form its lateral boundary. It contains the lateral hypothalamic nucleus, tuberomammillary nucleus, lateral tuberal nuclei, and fibers of the MEDIAL FOREBRAIN BUNDLE.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Cervix Uteri: The neck portion of the UTERUS between the lower isthmus and the VAGINA forming the cervical canal.Infusion Pumps, Implantable: Implanted fluid propulsion systems with self-contained power source for providing long-term controlled-rate delivery of drugs such as chemotherapeutic agents or analgesics. Delivery rate may be externally controlled or osmotically or peristatically controlled with the aid of transcutaneous monitoring.Glycoprotein Hormones, alpha Subunit: The alpha chain of pituitary glycoprotein hormones (THYROTROPIN; FOLLICLE STIMULATING HORMONE; LUTEINIZING HORMONE) and the placental CHORIONIC GONADOTROPIN. Within a species, the alpha subunits of these four hormones are identical; the distinct functional characteristics of these glycoprotein hormones are determined by the unique beta subunits. Both subunits, the non-covalently bound heterodimers, are required for full biologic activity.Receptors, FSH: Cell surface proteins that bind FOLLICLE STIMULATING HORMONE with high affinity and trigger intracellular changes influencing the behavior of cells.Receptors, Gonadotropin: Those protein complexes or molecular sites on the surfaces of gonadal and other sensitive cells that bind gonadotropins and thereby modify the functions of those cells; hCG, LH, and FOLLICLE STIMULATING HORMONE are the major specific gonadotropins.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Gonanes: Steroids containing the fundamental tetracyclic unit with no methyl groups at C-10 and C-13 and with no side chain at C-17. The concept includes both saturated and unsaturated derivatives.Pimozide: A diphenylbutylpiperidine that is effective as an antipsychotic agent and as an alternative to HALOPERIDOL for the suppression of vocal and motor tics in patients with Tourette syndrome. Although the precise mechanism of action is unknown, blockade of postsynaptic dopamine receptors has been postulated. (From AMA Drug Evaluations Annual, 1994, p403)Adrenalectomy: Excision of one or both adrenal glands. (From Dorland, 28th ed)Pregnancy Rate: The ratio of the number of conceptions (CONCEPTION) including LIVE BIRTH; STILLBIRTH; and fetal losses, to the mean number of females of reproductive age in a population during a set time period.Embryo Implantation: Endometrial implantation of EMBRYO, MAMMALIAN at the BLASTOCYST stage.Growth Hormone: A polypeptide that is secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Growth hormone, also known as somatotropin, stimulates mitosis, cell differentiation and cell growth. Species-specific growth hormones have been synthesized.Immunoradiometric Assay: Form of radioimmunoassay in which excess specific labeled antibody is added directly to the test antigen being measured.Trenbolone Acetate: An anabolic steroid used mainly as an anabolic agent in veterinary practice.Vesicular Inhibitory Amino Acid Transport Proteins: A family of vesicular neurotransmitter transporter proteins that sequester the inhibitory neurotransmitters GLYCINE; GAMMA-AMINOBUTYRIC ACID; and possibly GAMMA-HYDROXYBUTYRATE into SECRETORY VESICLES.Hypogonadism: Condition resulting from deficient gonadal functions, such as GAMETOGENESIS and the production of GONADAL STEROID HORMONES. It is characterized by delay in GROWTH, germ cell maturation, and development of secondary sex characteristics. Hypogonadism can be due to a deficiency of GONADOTROPINS (hypogonadotropic hypogonadism) or due to primary gonadal failure (hypergonadotropic hypogonadism).Oogenesis: The process of germ cell development in the female from the primordial germ cells through OOGONIA to the mature haploid ova (OVUM).Endorphins: One of the three major groups of endogenous opioid peptides. They are large peptides derived from the PRO-OPIOMELANOCORTIN precursor. The known members of this group are alpha-, beta-, and gamma-endorphin. The term endorphin is also sometimes used to refer to all opioid peptides, but the narrower sense is used here; OPIOID PEPTIDES is used for the broader group.Macaca: A genus of the subfamily CERCOPITHECINAE, family CERCOPITHECIDAE, consisting of 16 species inhabiting forests of Africa, Asia, and the islands of Borneo, Philippines, and Celebes.Macaca mulatta: A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Endometrium: The mucous membrane lining of the uterine cavity that is hormonally responsive during the MENSTRUAL CYCLE and PREGNANCY. The endometrium undergoes cyclic changes that characterize MENSTRUATION. After successful FERTILIZATION, it serves to sustain the developing embryo.Buserelin: A potent synthetic analog of GONADOTROPIN-RELEASING HORMONE with D-serine substitution at residue 6, glycine10 deletion, and other modifications.Hypothalamic Hormones: Peptide hormones produced by NEURONS of various regions in the HYPOTHALAMUS. They are released into the pituitary portal circulation to stimulate or inhibit PITUITARY GLAND functions. VASOPRESSIN and OXYTOCIN, though produced in the hypothalamus, are not included here for they are transported down the AXONS to the POSTERIOR LOBE OF PITUITARY before being released into the portal circulation.Macropodidae: A family of herbivorous leaping MAMMALS of Australia, New Guinea, and adjacent islands. Members include kangaroos, wallabies, quokkas, and wallaroos.Cholesterol Side-Chain Cleavage Enzyme: A mitochondrial cytochrome P450 enzyme that catalyzes the side-chain cleavage of C27 cholesterol to C21 pregnenolone in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP11A1 gene, catalyzes the breakage between C20 and C22 which is the initial and rate-limiting step in the biosynthesis of various gonadal and adrenal steroid hormones.Methoxychlor: An insecticide. Methoxychlor has estrogenic effects in mammals, among other effects.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Neuropeptides: Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.Aromatase: An enzyme that catalyzes the desaturation (aromatization) of the ring A of C19 androgens and converts them to C18 estrogens. In this process, the 19-methyl is removed. This enzyme is membrane-bound, located in the endoplasmic reticulum of estrogen-producing cells of ovaries, placenta, testes, adipose, and brain tissues. Aromatase is encoded by the CYP19 gene, and functions in complex with NADPH-FERRIHEMOPROTEIN REDUCTASE in the cytochrome P-450 system.
a b Values taken from day 1 after LH surge in: Stricker R, Eberhart R, Chevailler MC, Quinn FA, Bischof P, Stricker R (2006). " ... The highest levels are reached about 24 to 48 hours before the LH peak. In fact, the pre-ovulatory peak in estradiol represents ... estradiol levels briefly surge and reach their highest concentrations of any other time during the menstrual cycle.[59] ... the hypothalamic-pituitary events that lead to the luteinizing hormone surge, inducing ovulation. In the luteal phase, ...
Ovulation normally occurs 30 (± 2) hours after the beginning of the LH surge (when LH is first detectable in urine). The time ... Under the influence of the preovulatory LH surge, the first meiotic division of the oocytes is completed. The surge also ... The short-term drop in steroid hormones between the beginning of the LH surge and the event of ovulation may cause mid-cycle ... which lowers the levels of LH and FSH. This slowdown in LH and FSH production leads to the atresia (death) of most of the ...
Bowman, L.; Dilley, S.R.; Keverne, E.B. (1978). "Suppression of oestrogen-induced LH surges by social subordination in talapoin ... Being grouped with other females suppresses the young female's serum LH and prolactin. Exposure to the male elevates their LH ...
Progestogen negative feedback and the lack of estrogen positive feedback on LH release prevent a mid-cycle LH surge. Inhibition ... surge has been shown to precede the LH surge, suggesting that estrogen's main effect is on the hypothalamus, which controls ... There are many fertility testing methods, including urine test kits that detect the LH surge that occurs 24 to 36 hours before ... This process, known as the LH surge, starts around day 12 of the average cycle and may last 48 hours.[83] ...
Progestogen negative feedback and the lack of estrogen positive feedback on LH release prevent a mid-cycle LH surge. Inhibition ... In animals, a gonadotropin-releasing hormone (GnRH) surge has been shown to precede the LH surge, suggesting that estrogen's ... suggesting that estrogen acts directly on the pituitary to provoke the LH surge. The release of LH matures the egg and weakens ... This process, known as the LH surge, starts around day 12 of the average cycle and may last 48 hours. The exact mechanism of ...
Progestogen negative feedback and the lack of estrogen positive feedback on LH release prevent a LH surge. Inhibition of ... follicular development and the absence of a LH surge prevent ovulation. A secondary mechanism of action of all progestogen- ... LH) by the anterior pituitary. Decreased levels of FSH inhibit follicular development, preventing an increase in estradiol ...
Progestogen negative feedback and the lack of estrogen positive feedback on LH release prevent a mid-cycle LH surge. Inhibition ... of follicular development and the absence of a LH surge prevent ovulation. Estrogen was originally included in oral ... LH) by the anterior pituitary. Decreased levels of FSH inhibit follicular development, preventing an increase in estradiol ...
This causes a surge in levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This lasts from 24 to 36 ... Following a surge of luteinizing hormone (LH), an oocyte (immature egg cell) will be released into the uterine tube, where it ... Ovulation is triggered by a spike in the amount of FSH and LH released from the pituitary gland. During the luteal (post- ... Note that ovulation is characterized by a sharp spike in levels of luteinizing hormone (LH) and follicle-stimulating hormone ( ...
A surge of luteinising hormone (LH) occurs within minutes of mating. With multiple matings, the LH surge is greater and lasts ... and therefore causes an LH surge. Ovulation is triggered in induced ovulators by a LH surge from the anterior pituitary, which ... Studies have found that the Lutenising Hormone (LH) is crucial to bring about the induced ovulation. Disruption in LH surges in ... After mating, the LH levels in female cats surge, and the time to ovulation can be predicted to occur between 1-2 days later. ...
It starts late in fetal life and is terminated shortly before ovulation by the LH surge. Thus, although the majority of oocytes ...
The GnRH surge brings about a surge in LH and follicle stimulating hormone (FSH). Since females have a cyclic gonadal function ... When female rats are injected with testosterone there is no positive feedback occurring and no LH surge. Moreover, castrated ... Both males and females rats exhibit luteinizing hormone (LH) pulses in which LH is released from the anterior pituitary due to ... males will exhibit LH surges, similar to female cyclic gonadal behavior. Phoenix CH, Goy RW, Gerall AA, Young WC. Organizing ...
Removal of progesterone device produces a surge of GnRH, generating a pulse of LH that induces ovulation. Progesterone ... Low levels of GnRH prevent the emergence of a dominant follicle by reducing the release of LH and FSH hormones. Current ... A dominant follicle develops but there is no ovulation as LH release is prevented by suppression of GnRH. ...
Removal of progesterone device produces a surge of GnRH, generating a pulse of LH that induces ovulation. Synchronisation of ... Low levels of GnRH prevent the emergence of a dominant follicle by diminishing release of LH and FSH hormones. Current ... A dominant follicle develops but there is no ovulation as LH release is prevented by suppression of GnRH. ...
In females, an acute rise of LH ("LH surge") triggers ovulation and development of the corpus luteum. In males, where LH had ... The increase in LH production only lasts for 24 to 48 hours. This "LH surge" triggers ovulation, thereby not only releasing the ... During the reproductive years, typical levels are between 1-20 IU/L. Physiologic high LH levels are seen during the LH surge (v ... LH tests are not recommended for contraceptive practices, as the LH surge typically occurs after the beginning of the fertile ...
This surge may have been noticed by the crew. There was no sign of a reaction by the crew other than the throttle movements, ... During the recommissioning process, the "EPR LH" failure message was displayed. The left-hand EPR transmitter was therefore ... Additionally, on 27 June 2014, an engine surge resulted in a rejected take off, at about 80 knots. Due to this, No.1 engine, ... Both engines suffered a surge probably due to the plane's high angle of attack. Both engines RPM then decreased to values close ...
GDF9 is required just prior to the surge of luteinizing hormone (LH), a key event responsible for ovulation. Prior to the LH ... Strausberg RL, Feingold EA, Grouse LH, et al. (2003). "Generation and initial analysis of more than 15,000 full-length human ... surge, GDF9 supports the metabolic function of cumulus cells, allowing glycolysis and cholesterol biosynthesis. Cholesterol is ...
This induction of final maturation and release of oocytes is the physiological role the LH surge by luteinizing hormone. ...
Without oestrogen production, the balance of hormones is affected and there is no LH surge with is required for ovulation. ... It was also found that in two of the three birds, there was an decrease in testosterone and an increase in LH which suggests ... Baird, David T.; Swanston, Ian A.; McNEILLY, Alan S. (1981-06-01). "Relationship Between LH, FSH, and Prolactin Concentration ... LH) by the anterior pituitary. Pre-pubertal individuals that lack leptin fail to reach the pubertal stage. If given leptin ...
This results in a surge of LH from the pituitary, the same hormone that matures the eggs in natural cycles. LH has a much ... Luteinizing hormone (LH) in addition to FSH has evidence of increased pregnancy rate, but not of live birth rate. Using low ... shorter half-life than hCG, so that nearly all of the LH is cleared by the time of egg collection, or about 36 hours after ...
It may also be used when LH monitoring hasn't shown an LH surge by cycle day 18 (where cycle day 1 is the first day of the ... It is basically a replacement for the luteinizing hormone (LH) surge whose effects include final maturation in natural ... triggering oocyte release has been shown to decrease pregnancy chances compared to frequent monitoring with LH surge tests. ... Therefore, in such cases, triggering oocyte release is best reserved for women who require IUI and in whom LH monitoring proves ...
This surge is particularly important in infant boys as it helps with testicular descent into the scrotum. The surge of GnRH/LH/ ... People with KS/HH lack the surge of GnRH, LH, and FSH that normally occurs between birth and six months of age. ... Low levels of the gonadotropins LH and FSH.[2]. *Hypogonadism due to low levels of testosterone in men or oestrogen/ ... The lack of this surge can sometimes be used as a diagnostic tool if KS/HH is suspected in a newborn boy, but is not normally ...
Progestogen negative feedback and the lack of estrogen positive feedback on LH secretion prevent a mid-cycle LH surge. ... Inhibition of follicular development and the absence of an LH surge prevent ovulation.[91][92][93] ... LH) by the anterior pituitary. Decreased levels of FSH inhibit follicular development, preventing an increase in estradiol ...
A woman will urinate on an LH surge stick once or twice a day, starting a few days before suspected ovulation. Often the stick ... A commonly used ovulation predictor is the luteinizing hormone (LH) surge urine stick or ovulation predictor stick that helps ...
Ovulation may be predicted by the use of urine tests that detect the preovulatory LH surge, called ovulation predictor kits ( ... LH) on granulosa cells. Endocrine disruption may also directly decrease fertility, such as changed levels of gonadotropin- ...
With continued low levels of FSH and LH, the corpus luteum will atrophy.[3] The death of the corpus luteum results in falling ... This is known as a "secondary estrogen surge".[11][medical citation needed] ... After ovulation, the pituitary hormones-FSH and LH released from the anterior pituitary cause the remaining parts of the ... The hormones produced by the corpus luteum also suppress production of the FSH and LH that the corpus luteum needs to maintain ...
Pinto LH, Lamb RA (April 2006). "The M2 proton channels of influenza A and B viruses". The Journal of Biological Chemistry. 281 ... better quality and surge capacity.[218] Research on a universal influenza A vaccine, targeted against the external domain of ...
Although the etiology of OFC has not been established, the absence or insufficiency of the preovulatory LH surge is considered ... developed in cows with a history of pathologic puerperium have a reduced capacity to trigger the preovulatory LH surge. ...
... it causes a switch from negative feedback to positive feedback on LH & FSH. That... ... it causes a switch from negative feedback to positive feedback on LH & FSH. That is why we have a surge near the end of the ...
Age-related LH surge dysfunction correlates with reduced responsiveness of hypothalamic anteroventral periventricular nucleus ... Age-related LH surge dysfunction correlates with reduced responsiveness of hypothalamic anteroventral periventricular nucleus ... Age-related LH surge dysfunction correlates with reduced responsiveness of hypothalamic anteroventral periventricular nucleus ... Age-related LH surge dysfunction correlates with reduced responsiveness of hypothalamic anteroventral periventricular nucleus ...
I think that Ive a short LH surge (I.e. period in which I get a positive test) of less than 24 h... ... I am a bit confused about what the surge means. I understand that it means that the surge in LH levels signals that ovulation ... So having sex on the day if the LH surge in prep for ovulation is what you are looking for. You know you are in the fertile ... So the idea of the LH surge is to allow you to get sperm in there before the egg. To get pregnant, you ideally want sperm ...
... the preovulatory LH surge and ovulation in farmed fallow deer, Dama dama ... The onset of the preovulatory LH surge (n = 8 observations) occurred at the onset of oestrus, with maximum LH surge ... 18 h after the peak of the preovulatory LH surge. (PDF emailed within 0-6 h: $19.90) ... A study was conducted to determine the timing of ovulation relative to the onset of oestrus and the preovulatory LH surge in ...
In terms of the luteinizing hormone (LH) surge, the ovulatory phase is most important. ... When LH surge does not happen. LH Surge does not occur in all women, but when LH does not surge there is often an underlying ... Increase in LH followed by surge. As the cycle comes closer to ovulation, LH levels start to rise. FSH, or follicle-stimulating ... There are two forms of over-the-counter LH surge testing kits, commonly marketed as ovulation tests. The first measures LH in ...
LH surge test results variable. Ovulating or not?. Ask a Doctor about Luteinizing hormone, Ask an OBGYN, Maternal and Fetal ... Once you have got a positive result for LH (Leutenizing hormone) surge, it means the LH levels have reached their peak and it ... A positive LH surge is a sure indicator of an impending ovulation.. Hope my answer is helpful. Write back if you have further ... On 11th day i tested my LH surge using a Ovulation kit.It showed me Positive. And Today -12th day also i tested but it did not ...
... but not all LH surges look the same. In this article, we talk about the importance of LH in the reproductive cycle. Read more. ... LH is the best indicator of imminent ovulation, ... LH will be present in urine from mid-morning. The LH surge ... Types of LH surge. A study looked at the characteristics of urinary LH and found that not all women are the same. LH surges ... The onset of the LH surge precedes ovulation by 35-44 hr, and the peak blood level of LH precedes ovulation by 10-12 hr. The LH ...
In females, an acute rise of LH ("LH surge") triggers ovulation and development of the corpus luteum. Does lh surge drop before ... just that your LH hormone is high. Does lh surge drop before, during or after ovulation? Babycenter. Can you have an lh surge ... The LH surge plays an important part in monitoring fertility in couples who are trying to get pregnant. Once the LH surge ... Does lh surge drop before, during or after ovulation? Babycenter. Can you have an lh surge but still not ovulate? Ava bracelet. ...
It is possible to have an LH surge and not release an egg, as well as absence of the LH surge altogether. It may also be ... An LH surge is a rapid increase in luteinizing hormone, which triggers the bodys release of a mature egg. This usually happens ... It is possible to get a positive result as a result of pregnancy and not an LH surge. The test will indicate a positive result ... Next comes the ovulatory phase, which begins on the day of the LH surge. The increase in luteinizing hormone sends a message to ...
... led to a surge in serum LH levels, with peak values at 1400 h. LHβ mRNA levels were slightly elevated by progesterone at 1400 h ... led to a surge in serum LH levels, with peak values at 1400 h. LHβ mRNA levels were slightly elevated by progesterone at 1400 h ... led to a surge in serum LH levels, with peak values at 1400 h. LHβ mRNA levels were slightly elevated by progesterone at 1400 h ... led to a surge in serum LH levels, with peak values at 1400 h. LHβ mRNA levels were slightly elevated by progesterone at 1400 h ...
Home > Community > Getting Pregnant > Fertility Treatments > Twinges from ovaries, no lh surge yet! ...
Like FSH, luteinizing hormone (LH) is released by the anterior pituitary in response to the action of GnRH. Also like FSH, LH ... What Are the Causes of No LH Surge? 6 Reasons for a Low FSH in Males ... In the absence of GnRH, FSH and LH levels fall and sperm production slows. This is one of the major mechanisms whereby male ... In men, LH causes the interstitial cells of the testes to produce the hormone testosterone. ...
Can you have a LH surge and ovulate on the same day?. ...
In summary, amounts of IGF-I or IGFBPs in preovulatory follicular fluid did not change in response to an LH surge, even though ... after the LH surge. Small follicles contained IGFBP-3 and other IGFBPs determined to be IGFBP-2, -4, and -5 by ...
LH surge. 16 days missed period. Sex during "ovulation window". Negative urine test x16. Period day 16 of missed period. What ...
Therefore more LH is released in a surge. This mimics the LH surge which occurs just before ovulation. ... Some fertility drugs contain FSH and LH. , which stimulate eggs to mature in the ovary. ... IVF involves giving a mother FSH and LH, to stimulate the maturation of several eggs in the ovary ... It works by blocking the action of oestrogens negative feedback on LH. ...
LH) surge, and at days 18, 29 and 45 post-LH surge and fatty acids were analysed using gas chromatography.\ud Setting:\ud ... Maternal Plasma DHA Levels Increase Prior to 29 Days Post-LH Surge in Women Undergoing Frozen Embryo Transfer: A Prospective, ... Maternal Plasma DHA Levels Increase Prior to 29 Days Post-LH Surge in Women Undergoing Frozen Embryo Transfer: A Prospective, ...
Estradiol level lh surge can u take cipro for a urinary tract infection ofloxacin ornidazole suspension uses le viagra ne ...
LH surge was also observed in the DRL rats with (±)-DOI. On the other hand, only 8% of DRL rats ovulated after treatment with ... LH surge was also observed in the DRL rats with (±)-DOI. On the other hand, only 8% of DRL rats ovulated after treatment with ... LH surge was also observed in the DRL rats with (±)-DOI. On the other hand, only 8% of DRL rats ovulated after treatment with ... LH surge was also observed in the DRL rats with (±)-DOI. On the other hand, only 8% of DRL rats ovulated after treatment with ...
... measuring LH and estradiol levels the day after an LH ≥ 17 IU/L and defining the surge as the first day of LH ≥ 17 IU/L in the ... They were divided into two groups: Group A included patients whose LH surge was defined as the first attainment of LH ≥ 17 IU/L ... patients whose LH level continued to rise and the surge was defined as the highest serum LH level occurring a day after LH ≥ 17 ... and estradiol in an effort to optimally identify the LH surge in NC-FET. It is a retrospective study that was performed in an ...
Pre-ovulatory LH/hCG surge decreases C-type natriuretic peptide secretion by ovarian granulosa cells to promote meiotic ... However, regulation of NPPC/CNP expression during the pre-ovulatory period and their regulation by the LH surge have not been ... oocytes are arrested at the diplotene stage of prophase I until meiotic resumption following the LH surge. Recently, C-type ... transcripts in granulosa cells during pre-ovulatory follicle growth in mice and a rapid decline induced by the pre-ovulatory LH ...
Multivariate Analysis: BP Surge. In the full model including LV hypertrophy and estimated GFR, a sleep-trough BP surge in the ... A blunted morning BP surge is an independent predictor of cardiovascular disease, whereas an excessive BP surge does not ... At variance with previous investigations, a greater morning BP surge, either expressed as sleep-trough or preawakening surge, ... the greater the morning BP surge and vice versa. Also, in the study by Metoki et al,7 the amplitude of the morning BP surge ...
A positive result indicates an "LH surge." This is a sign that ovulation may soon occur. ... You may miss your surge if you miss a day of testing. You may also not be able to detect a surge if you have an irregular ... You may need to test for several days to detect a surge in LH. ... Urinary LH immunoassays; At-home ovulation prediction test; LH ... LH urine tests are not the same as at home fertility monitors. Fertility monitors are digital handheld devices. They predict ...
  • To help clarify the physiological roles of c- fos , galanin, and GnRH in GnRH neurons and to determine the temporal relationships among these parameters, we measured circulating LH levels and cellular levels of c- fos , galanin, and GnRH mRNAs in GnRH neurons in ovariectomized rats over a 30 hr period bracketing a steroid-induced LH surge. (jneurosci.org)
  • Once the LH levels reach their peak, these levels start declining and the test can come negative after 24 hours. (healthcaremagic.com)
  • In men, LH causes the interstitial cells of the testes to produce the hormone testosterone. (livestrong.com)
  • LH is responsible for the production of the male hormone testosterone, which along with FSH is responsible for stimulating sperm production in the testicles. (ferring.com)
  • ud Design:\ud Women undergoing frozen embryo transfer were recruited and serial fasting blood samples were taken pre-luteinising hormone (LH) surge, and at days 18, 29 and 45 post-LH surge and fatty acids were analysed using gas chromatography. (openaire.eu)
  • They are at least 99% accurate in pinpointing the LH surge and can identify up to six fertile days during each cycle when you are most likely to become pregnant. (clearblue.com)
  • So the idea of the LH surge is to allow you to get sperm in there before the egg. (rollercoaster.ie)
  • Timing intercourse the day of the LH surge and the day after will ensure sperm exposure during this window of opportunity when egg fertilization is most likely. (rapidtest.com)