The effect of antiestrogens on egg yolk protein synthesis and estrogen-binding to chromatin in the rooster liver.

Nafoxidine and CI-628, two well known antiestrogenic compounds, reduce the stimulating effect of estradiol on the estrogen-binding capacity of the liver chromatin from roosters. In vitro both antiestrogens compete with [3H]estradiol for the binding sites on the liver chromatin. They inhibit the estrogen-induced synthesis of egg yolk proteins (vitellogenin) and fail to induce this estrogen-specific protein synthesis by themselves. They show the ability, however, to increase the estrogen-binding sites on the liver chromatin to some extent.