Immunohistochemical localization of inhibin-alpha in the testes of normal men and in men with testicular disorders.

Testicular biopsies from normal men and from men with testicular disorders were examined by immunohistochemistry for the presence of the inhibin-alpha subunit using two different antisera. Immunoreactive inhibin-alpha (irI-alpha) was found in Leydig cells in normal, oligospermic, and azoospermic men and in men with Klinefelter's syndrome, and it was also found in a Leydig cell tumour. hCG-treatment apparently increased the amount of immunoreactive inhibin-alpha, particularly in Leydig cells. Sertoli cells also contained irI-alpha but the staining intensity was considerably stronger in testes with impaired spermatogenesis or Sertoli-cell-only syndrome than in normal testes. It is suggested that the serum concentration of irI-alpha and inhibin in humans may, in a complex way, be related to both Leydig and Sertoli cell function, and that the relative contribution from these cells may change in cases of testicular malfunction.