Plasma testosterone (T), 5 alpha-dihydrotestosterone (DHT), T/DHT ratio, estrone (E1), estradiol (E2), E2/T ratio and 17-hydroxyprogesterone (17-OH-P) were measured in 70 patients with prostatic carcinoma (PCA) (T34, N01, M01), after endocrine therapy including: steroidal estrogens (polyestradiol phosphate = Estradurin monthly in injections of 80 mg; estradiol - 17 beta: 5 mg/d), nonsteroidal synthetic estrogens (DES: 5 mg/d; chlorotrianisene = TACE: 24 mg/d; DES-diphosphate = Honvan: 360 mg/d), orchidectomy and their combinations. All these forms of treatment lowered T, DHT, T/DHT ratio and 17-OH-P, the maximal suppression being observed after castration. No further decrease of the mentioned parameters was achieved by estrogen treatment of castrated patients, as compared with castration alone. In the noncastrated patients, steroidal estrogens were less effective than nonsteroidal ones, in terms of lowering T, DHT and T/DHT ratio. Significant decreases in estrone (p less than 0.05) and estradiol (p less than 0.01) levels were observed after nonsteroidal estrogen treatment and castration respectively, and extremely high values of circulating estrogens were found after steroidal estrogen administration.