ESTRADIOL RECEPTORS IN HUMAN LIVER

High affinity, low capacity estradiol binding activity was detected in cytoplasmic fractions from human liver. The binding activity was clearly differentiated from that due to contaminating serum proteins. Binding was specific for estrogens and there was no evidence of specifically bound androgen or progestin. Heating the cytoplasmic fraction or treatment with proteolytic enzymes destroyed activity, suggesting that the binding component was a protein. It is concluded that human liver contains a specific estradiol receptor with steroid specificity similar to that found in other estrogen target tissues. The presence of the estradiol receptor may be responsible for action of estradiol in modulating the synthesis of specific proteins in liver. © 1978.