Leydig cell function in men with disorders of spermatogenesis

Leydig cell function has been studied in patients with disorders of the seminiferous tubule; germinal cell aplasia, Klinefelter's syndrome, and severe germinal cell arrest. Testosterone, 1 estradiol, progesterone, 17-hydroxyprogesterone, 17-hydroxypregnenolone, and Δ⁵-androstenediol were measured before and after four days of hCG administration. Of the patient groups studied, only in Klinefelter's syndrome did Leydig cell function differ from normal. In Klinefelter's syndrome, there was a generally decreased steroid biosynthetic capacity of the Leydig cell, but no abnormal accumulation of steroid biosynthetic intermediates was detected. Plasma estradiol concentrations were normal suggesting that estradiol secretion remains normal in Klinefelter's syndrome. hCG produced an approximate doubling of the plasma concentrations of testosterone, 17-hydroxyprogesterone and estradiol in all subjects. The response of progesterone, 17-hydroxypregnenolone and Δ⁵-androstenediol were more variable, in keeping with their predominant adrenal origin in man.