Histochemical and ultrastructural study of prostatic tissue from baboons treated with antiprostatic drugs.

Histochemical and ultrastructural investigation of the prostate in baboons treated parenterally with saline revealed that the epithelial cells in the caudal prostatic lobe possess very high acid phosphatase activity, moderate nonspecific esterase activity and alkaline phosphatase activity, and little or no amino-peptidase or beta-glucuronidase activity. Only a few lipofuscin granules were found. Ultrastructurally, the epithelial cells had a characteristic polar appearance with a supranuclear zone dominated by large secretory vacuoles. Secretory granules were abundant in the apical zone. No clear difference was found between the cranial and the caudal prostate except that the acid phosphatase activity of the epithelial cells was much lower in the former. In baboons treated with estraumustine phosphate, diethylstilbestrol diphosphate, or with flutamide, i.e., drugs used in the treatment of advanced prostatic carcinoma, the epithelial cells in the caudal prostatic lobe showed a varying degree of atrophy, which was least in the flutamide-treated animals. The histologic changes were accompanied by only minor changes in the enzyme activities, but the number of histochemically demonstrable lipofuscin granules were substantially increased, a finding confirmed by electron microscopy. The drugs did not notably affect the cranial prostate. The findings showed that the caudal, but not the cranial, lobe of the prostate of the baboon resembles the human prostate and can be affected by drugs known to have a desirable effect on the carcinomatous human prostate.