COMPARATIVE STUDIES ON CENTRAL AND PERIPHERAL EFFECTS OF TWO EPIMERIC CATECHOLESTROGENS

Abstract
4-Hydroxyestradiol-17β and 4-hydroxyestradiol-17α(5 or 20 μg/d) were continuously s.c. infused for 3 days into ovariectomized adult rats. The serum levels of either epimer were virtually identical when the same dose was administered. 4-Hydroxyestradiol-17β significantly altered body and uterus weight and LH serum levels(negative and positive effects) at both doses tested. 4-Hydroxyestradiol-17α showed no effects even at the 20 ng/d dose. As both epimers have similar affinities for catechol O-methyltransferase,but their potencies regarding effects on LH serum levels differ markedly, it is concluded that the interaction of catecholestrogens with this enzyme is not essential for their effects on LH release.