Steroid hormone receptors in the prostate.

Specific receptors for dihydrotestosterone and estradiol-17-beta have been identified in cytosols of the human and baboon prostate. Binding of radioactive estradiol-17-beta to the 0.4 M potassium chloride extractable component of human prostate nuclei also was demonstrated. Cyproterone acetate and diethylstilbestrol, agents of known high affinity for dihydrotestosterone and estradiol-17-beta receptors, respectively, did not bind significantly to sex hormone binding globulin and, therefore, were useful as competitors in distinguishing binding of dihydrotestosterone and estradiol-17-beta to sex hormone binding globulin and to their specific receptors. Displacement of [3H]-estradiol-17-beta binding by diethylstilbestrol in cytosols of 11 needle biopsy specimens (mean equals 16.8 mg.) from prostatic cancer patients was analyzed. These preliminary data indicated a trend towards greater competition by diethylstilbestrol for high affinity binding sites in differentiated tumor specimens from men who were not receiving estrogen therapy. Objective and subjective responses to hormone therapy were recorded in these patients, whereas the disease in those men with low displacement assay values progressed.