Biomaterial Database

Further evidence that serotonin mediates the steroid-independent inhibition of luteinizing hormone secretion in anestrous ewes. 1990

C S Whisnant, and R L Goodman

Department of Physiology, West Virginia University Health Sciences Center, Morgantown 26506.

Two photoperiod-controlled neuroendocrine systems appear to suppress secretion of tonic luteinizing hormone (LH) in anestrous ewes: a steroid-independent system that decreases LH pulse frequency in ovariectomized ewes and a steroid-dependent system whereby estradiol gains the capacity to suppress LH pulse frequency in anestrus. This study was designed to test the hypothesis that serotonergic neurons inhibit LH pulse frequency in ovariectomized ewes and to examine the possible interaction of this system with the steroid-dependent inhibition of LH pulse frequency in the anestrous season. In Experiment 1, i.v. injection of serotonin receptor antagonist, methysergide, significantly increased LH pulse frequency in ovariectomized ewes during the anestrous season. In Experiment 2, we examined the effects of oral administration of parachlorophenylalanine for 5 days on the synthesis of serotonin. This treatment significantly increased LH pulse frequency in ovariectomized ewes, but had no effect on the negative feedback action of estradiol. These data support the hypothesis that a serotonergic neural system mediates the steroid-independent inhibition of LH pulse frequency in anestrous ewes and suggest that this system is not absolutely essential for the functioning of the steroid-dependent system responsible for the negative feedback action during the anestrous season.

UI	MeSH Term	Description	Entries
D007986	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.	ICSH (Interstitial Cell Stimulating Hormone),Interstitial Cell-Stimulating Hormone,LH (Luteinizing Hormone),Lutropin,Luteoziman,Luteozyman,Hormone, Interstitial Cell-Stimulating,Hormone, Luteinizing,Interstitial Cell Stimulating Hormone
D008784	Methysergide	An ergot derivative that is a congener of LYSERGIC ACID DIETHYLAMIDE. It antagonizes the effects of serotonin in blood vessels and gastrointestinal smooth muscle, but has few of the properties of other ergot alkaloids. Methysergide is used prophylactically in migraine and other vascular headaches and to antagonize serotonin in the carcinoid syndrome.	Dimethylergometrin,Methylmethylergonovine,Deseril,Desril,Désernil-Sandoz,Methysergide Dimaleate,Methysergide Maleate,Sansert,UML-491,Dimaleate, Methysergide,Désernil Sandoz,Maleate, Methysergide,UML 491,UML491
D010052	Ovariectomy	The surgical removal of one or both ovaries.	Castration, Female,Oophorectomy,Bilateral Ovariectomy,Bilateral Ovariectomies,Castrations, Female,Female Castration,Female Castrations,Oophorectomies,Ovariectomies,Ovariectomies, Bilateral,Ovariectomy, Bilateral
D010134	Fenclonine	A selective and irreversible inhibitor of tryptophan hydroxylase, a rate-limiting enzyme in the biosynthesis of serotonin (5-HYDROXYTRYPTAMINE). Fenclonine acts pharmacologically to deplete endogenous levels of serotonin.	p-Chlorophenylalanine,para-Chlorophenylalanine,CP-10,188,DL-3-(4-Chlorophenyl)alanine,Fenclonin,Fenclonine (L)-Isomer,Fenclonine Hydrobromide,Fenclonine Hydrochloride,Fenclonine, (D)-Isomer,Hydrobromide, Fenclonine,Hydrochloride, Fenclonine,para Chlorophenylalanine
D011985	Receptors, Serotonin	Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.	5-HT Receptor,5-HT Receptors,5-Hydroxytryptamine Receptor,5-Hydroxytryptamine Receptors,Receptors, Tryptamine,Serotonin Receptor,Serotonin Receptors,Tryptamine Receptor,Tryptamine Receptors,Receptors, 5-HT,Receptors, 5-Hydroxytryptamine,5 HT Receptor,5 HT Receptors,5 Hydroxytryptamine Receptor,5 Hydroxytryptamine Receptors,Receptor, 5-HT,Receptor, 5-Hydroxytryptamine,Receptor, Serotonin,Receptor, Tryptamine,Receptors, 5 HT,Receptors, 5 Hydroxytryptamine
D004958	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.	17 beta-Estradiol,Estradiol-17 beta,Oestradiol,17 beta-Oestradiol,Aerodiol,Delestrogen,Estrace,Estraderm TTS,Estradiol Anhydrous,Estradiol Hemihydrate,Estradiol Hemihydrate, (17 alpha)-Isomer,Estradiol Monohydrate,Estradiol Valerate,Estradiol Valeriante,Estradiol, (+-)-Isomer,Estradiol, (-)-Isomer,Estradiol, (16 alpha,17 alpha)-Isomer,Estradiol, (16 alpha,17 beta)-Isomer,Estradiol, (17-alpha)-Isomer,Estradiol, (8 alpha,17 beta)-(+-)-Isomer,Estradiol, (8 alpha,17 beta)-Isomer,Estradiol, (9 beta,17 alpha)-Isomer,Estradiol, (9 beta,17 beta)-Isomer,Estradiol, Monosodium Salt,Estradiol, Sodium Salt,Estradiol-17 alpha,Estradiol-17beta,Ovocyclin,Progynon-Depot,Progynova,Vivelle,17 beta Estradiol,17 beta Oestradiol,Estradiol 17 alpha,Estradiol 17 beta,Estradiol 17beta,Progynon Depot
D004971	Estrus	The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.
D005246	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.	Feedbacks
D005260	Female		Females
D000780	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.