Interference of gonadotropin-receptor interaction by synthetic estrogens.

In in vitro studies, the synthetic estrogens diethylstilbestrol and diethylstilbestrol sodium phosphate inhibited the binding of ¹²⁵I ovine lutropin to the rat ovarian receptor and ¹²⁵I ovine follitropin to the bovine testicular receptor. As the lutropin binding to receptor is affected to a greater extent, a preferential inhibitory effect may be suggested. Removal of the estrogens from the incubation medium by washing does not restore gonadotropin binding ability, indicating a strong effect. The two compounds were effective in displacing the labeled gonadotropin from the preformed receptor-hormone complex. This effect increased with time of incubation. It appears unlikely that the interference of gonadotropin-receptor interaction may be because of increased hormone and/or receptor degradation by the two compounds.