Androphilic proteins in the human prostate.

Dihydrotestosterone-binding protein in cytosols from human prostates was different from the R1881- and R5020-binding proteins. The R1881- and R5020-binding proteins in the cytosol were very similar and most of the binding sites for R1881 were capable of binding R5020. However, nuclear extracts showed equal binding to dihydrotestosterone and R1881, but not to R5020, suggesting that there might not be a progestin receptor in the human prostate. Maximum binding sites to dihydrotestosterone, R1881, and R5020 in cytosols were very similar among "normal" and pathological prostates except that dihydrotestosterone binding was higher in "normal" prostates than in the pathological ones. Histochemically, R1881-binding was observed in the epithelial cells and in malignant cells, but not in the stroma.