Open AccessFacilitation of Lordosis in Rats by a Metabolite of Luteinizing Hormone Releasing Hormone
Author(s) -
Tao Wu,
Marc J. Glucksman,
James L. Roberts,
Shaila K. Mani
Publication year - 2006
Publication title -
endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.674
H-Index - 257
eISSN - 1945-7170
pISSN - 0013-7227
DOI - 10.1210/en.2005-1646
Subject(s) - medicine , endocrinology , lordosis behavior , lordosis , metabolite , luteinizing hormone , ovulation , hormone , ovariectomized rat , chemistry , facilitation , biology , estradiol benzoate , neuroscience , radiography , radiology
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.