Two doses of Human Chorionic Gonadotrophin (100 and 200 i.u./day) and Testosterone Propionate (1 and 2 mg/day) were administered singly to adult male rats for seven successive days subcutaneously. The applied treatment resulted in significant increase in both testosterone and dihydrotestosterone serum levels without change in T / DHT ratio. The testis did not undergo appreciable change in weight. The accessory reproductive glands underwent significant ponderal increament.