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.Thyroid Hormones: Natural hormones secreted by the THYROID GLAND, such as THYROXINE, and their synthetic analogs.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.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.Parathyroid Hormone: A polypeptide hormone (84 amino acid residues) secreted by the PARATHYROID GLANDS which performs the essential role of maintaining intracellular CALCIUM levels in the body. Parathyroid hormone increases intracellular calcium by promoting the release of CALCIUM from BONE, increases the intestinal absorption of calcium, increases the renal tubular reabsorption of calcium, and increases the renal excretion of phosphates.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.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.Receptors, Thyroid Hormone: Specific high affinity binding proteins for THYROID HORMONES in target cells. They are usually found in the nucleus and regulate DNA transcription. These receptors are activated by hormones that leads to transcription, cell differentiation, and growth suppression. Thyroid hormone receptors are encoded by two genes (GENES, ERBA): erbA-alpha and erbA-beta for alpha and beta thyroid hormone receptors, respectively.Human Growth Hormone: A 191-amino acid polypeptide hormone secreted by the human adenohypophysis (PITUITARY GLAND, ANTERIOR), also known as GH or somatotropin. Synthetic growth hormone, termed somatropin, has replaced the natural form in therapeutic usage such as treatment of dwarfism in children with growth hormone deficiency.Adrenocorticotropic Hormone: An anterior pituitary hormone that stimulates the ADRENAL CORTEX and its production of CORTICOSTEROIDS. ACTH is a 39-amino acid polypeptide of which the N-terminal 24-amino acid segment is identical in all species and contains the adrenocorticotrophic activity. Upon further tissue-specific processing, ACTH can yield ALPHA-MSH and corticotrophin-like intermediate lobe peptide (CLIP).Pituitary Hormones: Hormones secreted by the PITUITARY GLAND including those from the anterior lobe (adenohypophysis), the posterior lobe (neurohypophysis), and the ill-defined intermediate lobe. Structurally, they include small peptides, proteins, and glycoproteins. They are under the regulation of neural signals (NEUROTRANSMITTERS) or neuroendocrine signals (HYPOTHALAMIC HORMONES) from the hypothalamus as well as feedback from their targets such as ADRENAL CORTEX HORMONES; ANDROGENS; ESTROGENS.Triiodothyronine: A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.Juvenile Hormones: Compounds, either natural or synthetic, which block development of the growing insect.Hormone Replacement Therapy: Therapeutic use of hormones to alleviate the effects of hormone deficiency.Growth Hormone-Releasing Hormone: A peptide of 44 amino acids in most species that stimulates the release and synthesis of GROWTH HORMONE. GHRF (or GRF) is synthesized by neurons in the ARCUATE NUCLEUS of the HYPOTHALAMUS. After being released into the pituitary portal circulation, GHRF stimulates GH release by the SOMATOTROPHS in the PITUITARY GLAND.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.Corticotropin-Releasing Hormone: A peptide of about 41 amino acids that stimulates the release of ADRENOCORTICOTROPIC HORMONE. CRH is synthesized by neurons in the PARAVENTRICULAR NUCLEUS of the HYPOTHALAMUS. After being released into the pituitary portal circulation, CRH stimulates the release of ACTH from the PITUITARY GLAND. CRH can also be synthesized in other tissues, such as PLACENTA; ADRENAL MEDULLA; and TESTIS.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.Peptide Hormones: Hormones synthesized from amino acids. They are distinguished from INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS in that their actions are systemic.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.Thyroxine: The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism.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.Anti-Mullerian Hormone: A glycoprotein that causes regression of MULLERIAN DUCTS. It is produced by SERTOLI CELLS of the TESTES. In the absence of this hormone, the Mullerian ducts develop into structures of the female reproductive tract. In males, defects of this hormone result in persistent Mullerian duct, a form of MALE PSEUDOHERMAPHRODITISM.Gonadal Hormones: Hormones produced by the GONADS, including both steroid and peptide hormones. The major steroid hormones include ESTRADIOL and PROGESTERONE from the OVARY, and TESTOSTERONE from the TESTIS. The major peptide hormones include ACTIVINS and INHIBINS.Thyroid Hormone Receptors beta: High affinity receptors for THYROID HORMONES, especially TRIIODOTHYRONINE. These receptors are usually found in the nucleus where they regulate DNA transcription. They are encoded by the THRB gene (also known as NR1A2, THRB1, or ERBA2 gene) as several isoforms produced by alternative splicing. Mutations in the THRB gene cause THYROID HORMONE RESISTANCE SYNDROME.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.Pituitary Hormones, Anterior: Hormones secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Structurally, they include polypeptide, protein, and glycoprotein molecules.Thyrotropin: A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity.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.Gastrointestinal Hormones: HORMONES secreted by the gastrointestinal mucosa that affect the timing or the quality of secretion of digestive enzymes, and regulate the motor activity of the digestive system organs.Thyroid Hormone Receptors alpha: High affinity receptors for THYROID HORMONES, especially TRIIODOTHYRONINE. These receptors are usually found in the nucleus where they regulate DNA transcription. They are encoded by the THRA gene (also known as NR1A1, THRA1, ERBA or ERBA1 gene) as several isoforms produced by alternative splicing.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.Insect Hormones: Hormones secreted by insects. They influence their growth and development. Also synthetic substances that act like insect hormones.Hormone 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.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.Invertebrate Hormones: Hormones produced by invertebrates, usually insects, mollusks, annelids, and helminths.Pituitary Hormones, Posterior: Hormones released from the neurohypophysis (PITUITARY GLAND, POSTERIOR). They include a number of peptides which are formed in the NEURONS in the HYPOTHALAMUS, bound to NEUROPHYSINS, and stored in the nerve terminals in the posterior pituitary. Upon stimulation, these peptides are released into the hypophysial portal vessel blood.Receptors, Somatotropin: Cell surface proteins that bind GROWTH HORMONE with high affinity and trigger intracellular changes influencing the behavior of cells. Activation of growth hormone receptors regulates amino acid transport through cell membranes, RNA translation to protein, DNA transcription, and protein and amino acid catabolism in many cell types. Many of these effects are mediated indirectly through stimulation of the release of somatomedins.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.Melanocyte-Stimulating Hormones: Peptides with the ability to stimulate pigmented cells MELANOCYTES in mammals and MELANOPHORES in lower vertebrates. By stimulating the synthesis and distribution of MELANIN in these pigmented cells, they increase coloration of skin and other tissue. MSHs, derived from pro-opiomelanocortin (POMC), are produced by MELANOTROPHS in the INTERMEDIATE LOBE OF PITUITARY; CORTICOTROPHS in the ANTERIOR LOBE OF PITUITARY, and the hypothalamic neurons in the ARCUATE NUCLEUS OF HYPOTHALAMUS.Testicular Hormones: Hormones produced in the testis.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.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.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.Hypothyroidism: A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA.Receptor, Parathyroid Hormone, Type 1: A parathyroid hormone receptor subtype that recognizes both PARATHYROID HORMONE and PARATHYROID HORMONE-RELATED PROTEIN. It is a G-protein-coupled receptor that is expressed at high levels in BONE and in KIDNEY.Placental Hormones: Hormones produced by the placenta include CHORIONIC GONADOTROPIN, and PLACENTAL LACTOGEN as well as steroids (ESTROGENS; PROGESTERONE), and neuropeptide hormones similar to those found in the hypothalamus (HYPOTHALAMIC HORMONES).Pancreatic Hormones: Peptide hormones secreted into the blood by cells in the ISLETS OF LANGERHANS of the pancreas. The alpha cells secrete glucagon; the beta cells secrete insulin; the delta cells secrete somatostatin; and the PP cells secrete pancreatic polypeptide.Ovariectomy: The surgical removal of one or both ovaries.Receptors, Thyrotropin-Releasing Hormone: Cell surface receptors that bind thyrotropin releasing hormone (TRH) with high affinity and trigger intracellular changes which influence the behavior of cells. Activated TRH receptors in the anterior pituitary stimulate the release of thyrotropin (thyroid stimulating hormone, TSH); TRH receptors on neurons mediate neurotransmission by TRH.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.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.Receptors, Parathyroid Hormone: Cell surface proteins that bind PARATHYROID HORMONE with high affinity and trigger intracellular changes which influence the behavior of cells. Parathyroid hormone receptors on BONE; KIDNEY; and gastrointestinal cells mediate the hormone's role in calcium and phosphate homeostasis.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.Insulin-Like Growth Factor I: A well-characterized basic peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like, and mitogenic activities. This growth factor has a major, but not absolute, dependence on GROWTH HORMONE. It is believed to be mainly active in adults in contrast to INSULIN-LIKE GROWTH FACTOR II, which is a major fetal growth factor.Hypophysectomy: Surgical removal or destruction of the hypophysis, or pituitary gland. (Dorland, 28th ed)Thyroid Gland: A highly vascularized endocrine gland consisting of two lobes joined by a thin band of tissue with one lobe on each side of the TRACHEA. It secretes THYROID HORMONES from the follicular cells and CALCITONIN from the parafollicular cells thereby regulating METABOLISM and CALCIUM level in blood, respectively.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.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.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).Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Thyroid Hormone Resistance Syndrome: An inherited autosomal recessive trait, characterized by peripheral resistance to THYROID HORMONES and the resulting elevation in serum levels of THYROXINE and TRIIODOTHYRONINE. This syndrome is caused by mutations of gene THRB encoding the THYROID HORMONE RECEPTORS BETA in target cells. HYPOTHYROIDISM in these patients is partly overcome by the increased thyroid hormone levels.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Insulin: A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).Time Factors: Elements of limited time intervals, contributing to particular results or situations.Postmenopause: The physiological period following the MENOPAUSE, the permanent cessation of the menstrual life.Steroids: A group of polycyclic compounds closely related biochemically to TERPENES. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. (From Hawley's Condensed Chemical Dictionary, 11th ed)Receptors, FSH: Cell surface proteins that bind FOLLICLE STIMULATING HORMONE with high affinity and trigger intracellular changes influencing the behavior of cells.Receptors, Pituitary Hormone-Regulating Hormone: Cell surface receptors that bind the hypothalamic hormones regulating pituitary cell differentiation, proliferation, and hormone synthesis and release, including the pituitary-releasing and release-inhibiting hormones. The pituitary hormone-regulating hormones are also released by cells other than hypothalamic neurons, and their receptors also occur on non-pituitary cells, especially brain neurons, where their role is less well understood. Receptors for dopamine, which is a prolactin release-inhibiting hormone as well as a common neurotransmitter, are not included here.alpha-MSH: A 13-amino acid peptide derived from proteolytic cleavage of ADRENOCORTICOTROPIC HORMONE, the N-terminal segment of ACTH. ACTH (1-13) is amidated at the C-terminal to form ACTH (1-13)NH2 which in turn is acetylated to form alpha-MSH in the secretory granules. Alpha-MSH stimulates the synthesis and distribution of MELANIN in MELANOCYTES in mammals and MELANOPHORES in lower vertebrates.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.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.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.Pituitary Neoplasms: Neoplasms which arise from or metastasize to the PITUITARY GLAND. The majority of pituitary neoplasms are adenomas, which are divided into non-secreting and secreting forms. Hormone producing forms are further classified by the type of hormone they secrete. Pituitary adenomas may also be characterized by their staining properties (see ADENOMA, BASOPHIL; ADENOMA, ACIDOPHIL; and ADENOMA, CHROMOPHOBE). Pituitary tumors may compress adjacent structures, including the HYPOTHALAMUS, several CRANIAL NERVES, and the OPTIC CHIASM. Chiasmal compression may result in bitemporal HEMIANOPSIA.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.Iodide Peroxidase: A hemeprotein that catalyzes the oxidation of the iodide radical to iodine with the subsequent iodination of many organic compounds, particularly proteins. EC 1.11.1.8.Ghrelin: A 28-amino acid, acylated, orexigenic peptide that is a ligand for GROWTH HORMONE SECRETAGOGUE RECEPTORS. Ghrelin is widely expressed but primarily in the stomach in the adults. Ghrelin acts centrally to stimulate growth hormone secretion and food intake, and peripherally to regulate energy homeostasis. Its large precursor protein, known as appetite-regulating hormone or motilin-related peptide, contains ghrelin and obestatin.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Menopause: The last menstrual period. Permanent cessation of menses (MENSTRUATION) is usually defined after 6 to 12 months of AMENORRHEA in a woman over 45 years of age. In the United States, menopause generally occurs in women between 48 and 55 years of age.Thymus Hormones: Humoral factors secreted by the thymus gland. They participate in the development of the lymphoid system and the maturation of the cellular immune response.Glucagon: A 29-amino acid pancreatic peptide derived from proglucagon which is also the precursor of intestinal GLUCAGON-LIKE PEPTIDES. Glucagon is secreted by PANCREATIC ALPHA CELLS and plays an important role in regulation of BLOOD GLUCOSE concentration, ketone metabolism, and several other biochemical and physiological processes. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1511)Castration: Surgical removal or artificial destruction of gonads.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Hyperthyroidism: Hypersecretion of THYROID HORMONES from the THYROID GLAND. Elevated levels of thyroid hormones increase BASAL METABOLIC RATE.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Orchiectomy: The surgical removal of one or both testicles.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.Triiodothyronine, Reverse: A metabolite of THYROXINE, formed by the peripheral enzymatic monodeiodination of T4 at the 5 position of the inner ring of the iodothyronine nucleus.Growth Disorders: Deviations from the average values for a specific age and sex in any or all of the following: height, weight, skeletal proportions, osseous development, or maturation of features. Included here are both acceleration and retardation of growth.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.Metamorphosis, Biological: Profound physical changes during maturation of living organisms from the immature forms to the adult forms, such as from TADPOLES to frogs; caterpillars to BUTTERFLIES.Dwarfism, Pituitary: A form of dwarfism caused by complete or partial GROWTH HORMONE deficiency, resulting from either the lack of GROWTH HORMONE-RELEASING FACTOR from the HYPOTHALAMUS or from the mutations in the growth hormone gene (GH1) in the PITUITARY GLAND. It is also known as Type I pituitary dwarfism. Human hypophysial dwarf is caused by a deficiency of HUMAN GROWTH HORMONE during development.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.Plant Growth Regulators: Any of the hormones produced naturally in plants and active in controlling growth and other functions. There are three primary classes: auxins, cytokinins, and gibberellins.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Ovulation: The discharge of an OVUM from a rupturing follicle in the OVARY.Receptors, Corticotropin-Releasing Hormone: Cell surface proteins that bind corticotropin-releasing hormone with high affinity and trigger intracellular changes which influence the behavior of cells. The corticotropin releasing-hormone receptors on anterior pituitary cells mediate the stimulation of corticotropin release by hypothalamic corticotropin releasing factor. The physiological consequence of activating corticotropin-releasing hormone receptors on central neurons is not well understood.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.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.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.Receptors, Steroid: Proteins found usually in the cytoplasm or nucleus that specifically bind steroid hormones and trigger changes influencing the behavior of cells. The steroid receptor-steroid hormone complex regulates the transcription of specific genes.Corticosterone: An adrenocortical steroid that has modest but significant activities as a mineralocorticoid and a glucocorticoid. (From Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1437)Hypopituitarism: Diminution or cessation of secretion of one or more hormones from the anterior pituitary gland (including LH; FOLLICLE STIMULATING HORMONE; SOMATOTROPIN; and CORTICOTROPIN). This may result from surgical or radiation ablation, non-secretory PITUITARY NEOPLASMS, metastatic tumors, infarction, PITUITARY APOPLEXY, infiltrative or granulomatous processes, and other conditions.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.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.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).Receptors, Estrogen: 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.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.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.Kinetics: The rate dynamics in chemical or physical systems.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.Somatostatin: A 14-amino acid peptide named for its ability to inhibit pituitary GROWTH HORMONE release, also called somatotropin release-inhibiting factor. It is expressed in the central and peripheral nervous systems, the gut, and other organs. SRIF can also inhibit the release of THYROID-STIMULATING HORMONE; PROLACTIN; INSULIN; and GLUCAGON besides acting as a neurotransmitter and neuromodulator. In a number of species including humans, there is an additional form of somatostatin, SRIF-28 with a 14-amino acid extension at the N-terminal.Placental Lactogen: A polypeptide hormone of approximately 25 kDa that is produced by the SYNCYTIOTROPHOBLASTS of the PLACENTA, also known as chorionic somatomammotropin. It has both GROWTH HORMONE and PROLACTIN activities on growth, lactation, and luteal steroid production. In women, placental lactogen secretion begins soon after implantation and increases to 1 g or more a day in late pregnancy. Placental lactogen is also an insulin antagonist.Dexamethasone: An anti-inflammatory 9-fluoro-glucocorticoid.Sexual Maturation: Achievement of full sexual capacity in animals and in humans.Receptors, Pituitary Hormone: Cell surface proteins that bind pituitary hormones with high affinity and trigger intracellular changes influencing the behavior of cells. Since many pituitary hormones are also released by neurons as neurotransmitters, these receptors are also found in the nervous system.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.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, respectivelyBreast Neoplasms: Tumors or cancer of the human BREAST.Parathyroid Glands: Two pairs of small oval-shaped glands located in the front and the base of the NECK and adjacent to the two lobes of THYROID GLAND. They secrete PARATHYROID HORMONE that regulates the balance of CALCIUM; PHOSPHORUS; and MAGNESIUM in the body.Sex Characteristics: 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.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.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Dehydroepiandrosterone: A major C19 steroid produced by the ADRENAL CORTEX. It is also produced in small quantities in the TESTIS and the OVARY. Dehydroepiandrosterone (DHEA) can be converted to TESTOSTERONE; ANDROSTENEDIONE; ESTRADIOL; and ESTRONE. Most of DHEA is sulfated (DEHYDROEPIANDROSTERONE SULFATE) before secretion.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Estrus: The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.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.Leptin: A 16-kDa peptide hormone secreted from WHITE ADIPOCYTES. Leptin serves as a feedback signal from fat cells to the CENTRAL NERVOUS SYSTEM in regulation of food intake, energy balance, and fat storage.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Organ Size: The measurement of an organ in volume, mass, or heaviness.Ecdysterone: A steroid hormone that regulates the processes of MOLTING or ecdysis in insects. Ecdysterone is the 20-hydroxylated ECDYSONE.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.Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Receptors, Glucocorticoid: Cytoplasmic proteins that specifically bind glucocorticoids and mediate their cellular effects. The glucocorticoid receptor-glucocorticoid complex acts in the nucleus to induce transcription of DNA. Glucocorticoids were named for their actions on blood glucose concentration, but they have equally important effects on protein and fat metabolism. Cortisol is the most important example.Dihydrotestosterone: A potent androgenic metabolite of TESTOSTERONE. It is produced by the action of the enzyme 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE.Buserelin: A potent synthetic analog of GONADOTROPIN-RELEASING HORMONE with D-serine substitution at residue 6, glycine10 deletion, and other modifications.Endocrine System: The system of glands that release their secretions (hormones) directly into the circulatory system. In addition to the ENDOCRINE GLANDS, included are the CHROMAFFIN SYSTEM and the NEUROSECRETORY SYSTEMS.Thyroidectomy: Surgical removal of the thyroid gland. (Dorland, 28th ed)Acromegaly: A condition caused by prolonged exposure to excessive HUMAN GROWTH HORMONE in adults. It is characterized by bony enlargement of the FACE; lower jaw (PROGNATHISM); hands; FEET; HEAD; and THORAX. The most common etiology is a GROWTH HORMONE-SECRETING PITUITARY ADENOMA. (From Joynt, Clinical Neurology, 1992, Ch36, pp79-80)Glucocorticoids: A group of CORTICOSTEROIDS that affect carbohydrate metabolism (GLUCONEOGENESIS, liver glycogen deposition, elevation of BLOOD SUGAR), inhibit ADRENOCORTICOTROPIC HORMONE secretion, and possess pronounced anti-inflammatory activity. They also play a role in fat and protein metabolism, maintenance of arterial blood pressure, alteration of the connective tissue response to injury, reduction in the number of circulating lymphocytes, and functioning of the central nervous system.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.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Triptorelin Pamoate: A potent synthetic long-acting agonist of GONADOTROPIN-RELEASING HORMONE with D-tryptophan substitution at residue 6.Teriparatide: A polypeptide that consists of the 1-34 amino-acid fragment of human PARATHYROID HORMONE, the biologically active N-terminal region. The acetate form is given by intravenous infusion in the differential diagnosis of HYPOPARATHYROIDISM and PSEUDOHYPOPARATHYROIDISM. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1995)Receptors, Ghrelin: Transmembrane proteins that recognize and bind GHRELIN, a potent stimulator of GROWTH HORMONE secretion and food intake in mammals. Ghrelin receptors are found in the pituitary and HYPOTHALAMUS. They belong to the family of G-PROTEIN-COUPLED RECEPTORS.Receptor, Parathyroid Hormone, Type 2: A parathyroid hormone receptor subtype found in the BRAIN and the PANCREAS. It is a G-protein-coupled receptor with a ligand specificity that varies between homologs from different species.Pituitary-Adrenal System: The interactions between the anterior pituitary and adrenal glands, in which corticotropin (ACTH) stimulates the adrenal cortex and adrenal cortical hormones suppress the production of corticotropin by the anterior pituitary.Propylthiouracil: A thiourea antithyroid agent. Propythiouracil inhibits the synthesis of thyroxine and inhibits the peripheral conversion of throxine to tri-iodothyronine. It is used in the treatment of hyperthyroidism. (From Martindale, The Extra Pharmacopeoia, 30th ed, p534)Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.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.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).Ecdysone: A steroid hormone that regulates the processes of MOLTING or ecdysis in insects.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Estrogens, Conjugated (USP): A pharmaceutical preparation containing a mixture of water-soluble, conjugated estrogens derived wholly or in part from URINE of pregnant mares or synthetically from ESTRONE and EQUILIN. It contains a sodium-salt mixture of estrone sulfate (52-62%) and equilin sulfate (22-30%) with a total of the two between 80-88%. Other concomitant conjugates include 17-alpha-dihydroequilin, 17-alpha-estradiol, and 17-beta-dihydroequilin. The potency of the preparation is expressed in terms of an equivalent quantity of sodium estrone sulfate.Pro-Opiomelanocortin: A 30-kDa protein synthesized primarily in the ANTERIOR PITUITARY GLAND and the HYPOTHALAMUS. It is also found in the skin and other peripheral tissues. Depending on species and tissues, POMC is cleaved by PROHORMONE CONVERTASES yielding various active peptides including ACTH; BETA-LIPOTROPIN; ENDORPHINS; MELANOCYTE-STIMULATING HORMONES; and others (GAMMA-LPH; CORTICOTROPIN-LIKE INTERMEDIATE LOBE PEPTIDE; N-terminal peptide of POMC or NPP).Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.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).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).Adrenal Glands: A pair of glands located at the cranial pole of each of the two KIDNEYS. Each adrenal gland is composed of two distinct endocrine tissues with separate embryonic origins, the ADRENAL CORTEX producing STEROIDS and the ADRENAL MEDULLA producing NEUROTRANSMITTERS.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.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.Corpora Allata: Paired or fused ganglion-like bodies in the head of insects. The bodies secrete hormones important in the regulation of metamorphosis and the development of some adult tissues.Receptors, Cytoplasmic and Nuclear: Intracellular receptors that can be found in the cytoplasm or in the nucleus. They bind to extracellular signaling molecules that migrate through or are transported across the CELL MEMBRANE. Many members of this class of receptors occur in the cytoplasm and are transported to the CELL NUCLEUS upon ligand-binding where they signal via DNA-binding and transcription regulation. Also included in this category are receptors found on INTRACELLULAR MEMBRANES that act via mechanisms similar to CELL SURFACE RECEPTORS.Receptors, Thyrotropin: Cell surface proteins that bind pituitary THYROTROPIN (also named thyroid stimulating hormone or TSH) and trigger intracellular changes of the target cells. TSH receptors are present in the nervous system and on target cells in the thyroid gland. Autoantibodies to TSH receptors are implicated in thyroid diseases such as GRAVES DISEASE and Hashimoto disease (THYROIDITIS, AUTOIMMUNE).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.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).Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Blood Glucose: Glucose in blood.Receptors, Prolactin: Labile proteins on or in prolactin-sensitive cells that bind prolactin initiating the cells' physiological response to that hormone. Mammary casein synthesis is one of the responses. The receptors are also found in placenta, liver, testes, kidneys, ovaries, and other organs and bind and respond to certain other hormones and their analogs and antagonists. This receptor is related to the growth hormone receptor.Molting: Periodic casting off FEATHERS; HAIR; or cuticle. Molting is a process of sloughing or desquamation, especially the shedding of an outer covering and the development of a new one. This phenomenon permits growth in ARTHROPODS, skin renewal in AMPHIBIANS and REPTILES, and the shedding of winter coats in BIRDS and MAMMALS.Calcitriol: The physiologically active form of vitamin D. It is formed primarily in the kidney by enzymatic hydroxylation of 25-hydroxycholecalciferol (CALCIFEDIOL). Its production is stimulated by low blood calcium levels and parathyroid hormone. Calcitriol increases intestinal absorption of calcium and phosphorus, and in concert with parathyroid hormone increases bone resorption.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.Neuropeptides: Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Bone and Bones: 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.Antithyroid Agents: Agents that are used to treat hyperthyroidism by reducing the excessive production of thyroid hormones.Medroxyprogesterone Acetate: A synthetic progestin that is derived from 17-hydroxyprogesterone. It is a long-acting contraceptive that is effective both orally or by intramuscular injection and has also been used to treat breast and endometrial neoplasms.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.Dwarfism: A genetic or pathological condition that is characterized by short stature and undersize. Abnormal skeletal growth usually results in an adult who is significantly below the average height.Receptors, Neuropeptide: Cell surface receptors that bind specific neuropeptides with high affinity and trigger intracellular changes influencing the behavior of cells. Many neuropeptides are also hormones outside of the nervous system.Hyperparathyroidism: A condition of abnormally elevated output of PARATHYROID HORMONE (or PTH) triggering responses that increase blood CALCIUM. It is characterized by HYPERCALCEMIA and BONE RESORPTION, eventually leading to bone diseases. PRIMARY HYPERPARATHYROIDISM is caused by parathyroid HYPERPLASIA or PARATHYROID NEOPLASMS. SECONDARY HYPERPARATHYROIDISM is increased PTH secretion in response to HYPOCALCEMIA, usually caused by chronic KIDNEY DISEASES.Calcitonin: A peptide hormone that lowers calcium concentration in the blood. In humans, it is released by thyroid cells and acts to decrease the formation and absorptive activity of osteoclasts. Its role in regulating plasma calcium is much greater in children and in certain diseases than in normal adults.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Adrenal Cortex HormonesDNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Receptors, Retinoic Acid: Proteins in the nucleus or cytoplasm that specifically bind RETINOIC ACID or RETINOL and trigger changes in the behavior of cells. Retinoic acid receptors, like steroid receptors, are ligand-activated transcription regulators. Several types have been recognized.Leydig Cells: Steroid-producing cells in the interstitial tissue of the TESTIS. They are under the regulation of PITUITARY HORMONES; LUTEINIZING HORMONE; or interstitial cell-stimulating hormone. TESTOSTERONE is the major androgen (ANDROGENS) produced.Ecdysteroids: Steroids that bring about MOLTING or ecdysis in insects. Ecdysteroids include the endogenous insect hormones (ECDYSONE and ECDYSTERONE) and the insect-molting hormones found in plants, the phytoecdysteroids. Phytoecdysteroids are natural insecticides.Pituitary Function Tests: Examinations that evaluate functions of the pituitary gland.Puberty: A period in the human life in which the development of the hypothalamic-pituitary-gonadal system takes place and reaches full maturity. The onset of synchronized endocrine events in puberty lead to the capacity for reproduction (FERTILITY), development of secondary SEX CHARACTERISTICS, and other changes seen in ADOLESCENT DEVELOPMENT.Glucagon-Like Peptide 1: A peptide of 36 or 37 amino acids that is derived from PROGLUCAGON and mainly produced by the INTESTINAL L CELLS. GLP-1(1-37 or 1-36) is further N-terminally truncated resulting in GLP-1(7-37) or GLP-1-(7-36) which can be amidated. These GLP-1 peptides are known to enhance glucose-dependent INSULIN release, suppress GLUCAGON release and gastric emptying, lower BLOOD GLUCOSE, and reduce food intake.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.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.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.Premenopause: The period before MENOPAUSE. In premenopausal women, the climacteric transition from full sexual maturity to cessation of ovarian cycle takes place between the age of late thirty and early fifty.Eating: The consumption of edible substances.