Inhibition of LH release by CRF may be partially mediated through hypothalamic beta-endorphin release

Corticotropin releasing factor (CRF) given i.c.v. at doses of 0.02-2 nmol, significantly inhibited luteinising hormone (LH) secretion in castrate male rats. The luteinising hormone releasing hormone (LHRH) release from hypothalamic slices superfused in vitro with CRF (10(-12)M - 10(-8)M) was markedly reduced. In rats that had been infused with naloxone 2 days prior to testing with 0.2 nmol CRF, the effect of the CRF was significantly reduced. Together, these findings indicate that CRF inhibits LH secretion by inhibiting LHRH release from the hypothalamus, and that the latter action involves endogenous opioid peptides.