Luteolytic Agents: Chemical compounds causing LUTEOLYSIS or degeneration.Luteolysis: Degradation of CORPUS LUTEUM. In the absence of pregnancy and diminishing trophic hormones, the corpus luteum undergoes luteolysis which is characterized by the involution and cessation of its endocrine function.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.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.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.Cloprostenol: A synthetic prostaglandin F2alpha analog. The compound has luteolytic effects and is used for the synchronization of estrus in cattle.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.Corpus Luteum Maintenance: Process of maintaining the functions of CORPORA LUTEA, specifically PROGESTERONE production which is regulated primarily by pituitary LUTEINIZING HORMONE in cycling females, and by PLACENTAL HORMONES in pregnant females. The ability to maintain luteal functions is important in PREGNANCY MAINTENANCE.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.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.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.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.Estrus: The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.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).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.Receptors, Oxytocin: Cell surface proteins that bind oxytocin with high affinity and trigger intracellular changes which influence the behavior of cells. Oxytocin receptors in the uterus and the mammary glands mediate the hormone's stimulation of contraction and milk ejection. The presence of oxytocin and oxytocin receptors in neurons of the brain probably reflects an additional role as a neurotransmitter.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.Pregnancy, Animal: The process of bearing developing young (EMBRYOS or FETUSES) in utero in non-human mammals, beginning from FERTILIZATION to BIRTH.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.20-Hydroxysteroid Dehydrogenases: A group of enzymes that catalyze the reversible reduction-oxidation reaction of 20-hydroxysteroids, such as from a 20-ketosteroid to a 20-alpha-hydroxysteroid (EC 1.1.1.149) or to a 20-beta-hydroxysteroid (EC 1.1.1.53).Prostaglandins F, Synthetic: Analogs or derivatives of prostaglandins F that do not occur naturally in the body. They do not include the product of the chemical synthesis of hormonal PGF.20-alpha-Hydroxysteroid Dehydrogenase: An enzymes that catalyzes the reversible reduction-oxidation reaction of 20-alpha-hydroxysteroids, such as from PROGESTERONE to 20-ALPHA-DIHYDROPROGESTERONE.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.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Pregnancy Proteins: Proteins produced by organs of the mother or the PLACENTA during PREGNANCY. These proteins may be pregnancy-specific (present only during pregnancy) or pregnancy-associated (present during pregnancy or under other conditions such as hormone therapy or certain malignancies.)Receptors, Prostaglandin: Cell surface receptors that bind prostaglandins with high affinity and trigger intracellular changes which influence the behavior of cells. Prostaglandin receptor subtypes have been tentatively named according to their relative affinities for the endogenous prostaglandins. They include those which prefer prostaglandin D2 (DP receptors), prostaglandin E2 (EP1, EP2, and EP3 receptors), prostaglandin F2-alpha (FP receptors), and prostacyclin (IP receptors).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.Callithrix: A genus of the subfamily CALLITRICHINAE occurring in forests of Brazil and Bolivia and containing seventeen species.Ovulation: The discharge of an OVUM from a rupturing follicle in the OVARY.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).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.Hydroxyprostaglandin Dehydrogenases: Catalyzes reversibly the oxidation of hydroxyl groups of prostaglandins.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.Dystocia: Slow or difficult OBSTETRIC LABOR or CHILDBIRTH.Fetal Hypoxia: Deficient oxygenation of FETAL BLOOD.Palpation: Application of fingers with light pressure to the surface of the body to determine consistence of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs.Uterine Contraction: Contraction of the UTERINE MUSCLE.Obstetric Nursing: A nursing specialty involving nursing care given to the pregnant patient before, after, or during childbirth.Anthropology, Physical: The comparative science dealing with the physical characteristics of humans as related to their origin, evolution, and development in the total environment.Ketorolac Tromethamine: A pyrrolizine carboxylic acid derivative structurally related to INDOMETHACIN. It is a non-steroidal anti-inflammatory agent used for analgesia for postoperative pain and inhibits cyclooxygenase activity.Tromethamine: An organic amine proton acceptor. It is used in the synthesis of surface-active agents and pharmaceuticals; as an emulsifying agent for cosmetic creams and lotions, mineral oil and paraffin wax emulsions, as a biological buffer, and used as an alkalizer. (From Merck, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p1424)Melengestrol Acetate: A 6-methyl PROGESTERONE acetate with reported glucocorticoid activity and effect on ESTRUS.Dictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.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).Body Modification, Non-Therapeutic: The wounding of the body or body parts by branding, cutting, piercing (BODY PIERCING), or TATTOOING as a cultural practice or expression of creativity or identity.Toremifene: A first generation selective estrogen receptor modulator (SERM). Like TAMOXIFEN, it is an estrogen agonist for bone tissue and cholesterol metabolism but is antagonistic on mammary and uterine tissue.History, 20th Century: Time period from 1901 through 2000 of the common era.Tamoxifen: One of the SELECTIVE ESTROGEN RECEPTOR MODULATORS with tissue-specific activities. Tamoxifen acts as an anti-estrogen (inhibiting agent) in the mammary tissue, but as an estrogen (stimulating agent) in cholesterol metabolism, bone density, and cell proliferation in the ENDOMETRIUM.Goserelin: A synthetic long-acting agonist of GONADOTROPIN-RELEASING HORMONE. Goserelin is used in treatments of malignant NEOPLASMS of the prostate, uterine fibromas, and metastatic breast cancer.Breast Neoplasms: Tumors or cancer of the human BREAST.Antineoplastic Agents, Hormonal: Antineoplastic agents that are used to treat hormone-sensitive tumors. Hormone-sensitive tumors may be hormone-dependent, hormone-responsive, or both. A hormone-dependent tumor regresses on removal of the hormonal stimulus, by surgery or pharmacological block. Hormone-responsive tumors may regress when pharmacologic amounts of hormones are administered regardless of whether previous signs of hormone sensitivity were observed. The major hormone-responsive cancers include carcinomas of the breast, prostate, and endometrium; lymphomas; and certain leukemias. (From AMA Drug Evaluations Annual 1994, p2079)