[Simultaneous radioimmunoassay of androstenedione, testosterone and dihydrotestosterone. Application to the study of Leydig cell function].

A radioimmunological method for simultaneous dosage of androstenedione, testosterone and dihyhydrotestosterone is described. This technique was applied to the study of the secretions of Leydig cells removed from hypophysectomized boar testis, in organ cultures. The releasing kinetic of the 3 steroids under hCG influence was studied; after 12 days of culture, the medium was analysed during 96 hours (8 periods of 12 hours); the steroid production started immediately and showed a progressive increase then slightly slowed down at the end of the 4 days.