title: Progesterone and 20 alpha-hydroxyprogesterone stimulate the in vitro release of GnRH by the isolated mediobasal hypothalamus.
abstract: An in vitro perifusion system was used to investigate the effect of progesterone (P4) and 20 alpha-hydroxyprogesterone (20 alpha-OHP) on the release of GnRH from isolated hypothalamic tissue of the adult ovariectomized estradiol-17 beta primed rat. Pulse delivery of P4 stimulated GnRH release not only from the isolated mediobasal hypothalamus-anterior hypothalamus-preoptic area (MBH-AHPOA) complex but also from the MBH alone. Release of GnRH from the MBH was also increased by 20 alpha-OHP. These results suggest that the in vivo increase of circulating P4 or 20 alpha-OHP associated with the initiation of the preovulatory LH surge may play a role in regulating the timing or amplitude of this surge by directly stimulating the release of GnRH from the MBH.
mesh_terms: D000818:Animals; D002369:Castration; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D006908:Hydroxyprogesterones / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D006908:Hydroxyprogesterones; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol; D011189:Potassium Chloride