Effect of pretreatment of long-term ovariectomized (OVX) rats with a competitive LRH antagonist on FSH release in vitro.
The effect of a single sc injection of an LRH antagonist ((Ac-D-p-Cl-Phe1,2,D-Trp3,D-Phe6,D-Ala10)-LRH, Org 30093) into OVX rats on FSH release 24 h later was studied. Plasma FSH was decreased but pituitary FSH content was not changed. Incubation of the pituitary glands during 4 h resulted in a decreased basal release. FSH release induced by a low concentration of LRH (1 ng/ml) was depressed but that of a high concentration (10 000 ng/ml) was augmented in comparison to FSH release induced in control glands. However, pretreatment with the antagonist had no specific effect on FSH release in vitro induced by high K+ or high K+ plus mbcAMP and theophylline, indicating that the changes of pituitary responsiveness to LRH are not caused by those parts of the secretory mechanism which are stimulated by these secretagogues. Moreover, it is concluded that the changes of pituitary LH release induced by administration of an LRH antagonist also concern FSH.
D000818:Animals; D002369:Castration; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D007106:Immune Sera; D007986:Luteinizing Hormone / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D007106:Immune Sera; D007987:Gonadotropin-Releasing Hormone; C039243:LHRH,(N)-Ac-Trp(1)-(4-Cl-Phe)(2)-Trp(3)-Phe(6)-AlaNH2(10)-; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone