Evidence for a pituitary site of action for the acute inhibition of LH release by estrogen in the rat.

Abstract

Intravenous administration of estradiol in doses of 20 ng or more was capable of inhibiting LH release in ovariectomized rats as indicated by a decrease in plasma LH determined by radioimmunoassay. The inhibition came on within 1 hr and could persist for up to 4 hr after a single injection. The decrease in plasma LH which followed the injection of estradiol was at least in part caused by a decreased sensitivity of the pituitary gland to LRF since the increment in plasma LH in response to injection of the synthetic decapeptide was significantly decreased in estradiol—treated animals. Endocrinology92: 1680, 1973)