Facilitation of lordosis in rats by a metabolite of luteinizing hormone releasing hormone.
In the female rat, ovulation is preceded by a marked increase in the release of the decapeptide, LHRH, culminating in a preovulatory LH surge, which coincides with a period of sexual receptivity. The decapeptide, LHRH, is processed by a zinc metalloendopeptidase EC 3.4.24.15 (EP24.15) that cleaves the hormone at the Tyr(5)-Gly(6) bond. We have previously reported that the autoregulation of LHRH gene expression can also be mediated by its metabolite, LHRH-(1-5). Given the central function of LHRH in reproduction and reproductive behavior, we examined the role of the metabolite, LHRH-(1-5), in mediation of LHRH-facilitated reproductive behavior. Intracerebroventricular administration of LHRH-(1-5) facilitated sexual behavior responses, similar to those facilitated by the decapeptide LHRH, in ovariectomized estradiol-primed female rats. Furthermore, immunoneutralization of EP24.15 resulted in the inhibition of the LHRH-facilitated lordosis but had no inhibitory effects on LHRH-(1-5)-facilitated lordosis. The LHRH antagonist, Antide, was capable of inhibiting LHRH-facilitated lordosis, without affecting LHRH-(1-5)-facilitated lordosis. Collectively, these results suggest a role for LHRH metabolites in the facilitation of female receptive behavior in rats.
Wu
T J
TJ
Department of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA. twu@usuhs.mil
Glucksman
Marc J
MJ
Roberts
James L
JL
Mani
Shaila K
SK
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D002404:Catheterization; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000378:metabolism; D009424:Nervous System Physiological Phenomena; D009474:Neurons / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D010052:Ovariectomy; D010060:Ovulation; D010455:Peptides / Q000737:chemistry; D011187:Posture; D011817:Rabbits; D016634:Radiosurgery; D051381:Rats; D017207:Rats, Sprague-Dawley; D012726:Sexual Behavior, Animal
D009842:Oligopeptides; D010455:Peptides; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; C057022:iturelix