| Abstract: | We examined in vitro LHRH release as a function of time after ovariectomy (OVX). Adult female rats (diestrous day 1 and 11-16, 61-68, and more than 120 days post-OVX) were decapitated, and the suprachiasmatic-medial preoptic area-medial basal hypothalamus was removed and superfused in vitro. There was a statistically significant (P less than 0.05) 2-fold decrease in mean in vitro LHRH release 11-16 days post-OVX that returned to levels observed in diestrous day 1 females 60 days post-OVX. LHRH cycle amplitudes of 11- to 16-day ovariectomized rats were reduced and significantly lower (P less than 0.05) than those of more than 120-day ovariectomized rats. These results indicate a complex relationship between ovarian steroid hormone removal and LHRH pulse generator function that is only revealed after direct measurement of LHRH release. |
