Investigations on pituitary and Leydig cell function in chronic hemodialysis and after renal transplantation

The hypothalamus-pituitary-Leydig cell axis was investigated in 20 male patients undergoing intermittent hemodialysis and in 21 male patients following renal transplantation compared to normal controls. Plasma testosterone as well as luteinizing hormone and follicle stimulating hormone were determined by radioimmunoassay under basal conditions and after stimulation with choriongonadotropic hormone and hypothalamus releasing hormone respectively. Suppressed Leydig cell function has been demonstrated in dialysed patients as well as in patients after renal transplantation. The Leydig cell insufficiency is more pronounced in the hemodialysed patients. None of these showed testosterone levels in the normal range. They are different in various dialysis schedules. In contrast Leydig cell function is much better in patients after renal transplantation compared to those undergoing intermittent hemodialysis. But even after renal transplantation a diminished Leydig cell function takes place. The degree of Leydig cell insufficiency however varies individually. In a few cases Leydig cell function is restored completely after transplantation. It remains uncertain whether the duration of the posttransplantation period or the function of the graft effects Leydig cell function. Anterior lobe insufficiency has been excluded since plasma concentrations of gonadotropins were slightly elevated before and after LH-RH stimulation as compared to normals.