Investigations on Leydig cell function and regulation after renal transplantation.

The hypothalamic-hypophyseal-Leydig cell axis was investigated in 17 male patients following renal transplantation. Plasma levels of testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) were determined by radioimmunoassay under basal conditions and after stimulation with chorionic gonadotrophin (HCG) and hypothalamic releasing hormone (LH/FSH-RH) respectively. The investigations were carried out one to five years after renal transplantation. It was demonstrated, that primary dysfunction of Leydig cells may occur after renal transplantation. In some cases however normal Leydig cell function with adequate testosterone secretion may return. It remains uncertain, whether the Leydig cell dysfunction is a result of preexisting toxic uremic damage or whether it is due to immunosuppressive therapy with prednisone and azathioprine.