Hypogonadism in male hemodialysis patients has been previously reported. However, its precise pathogenesis has not yet been clarified. Mepitiostane and nandrolone decanoate are anabolic steroids prescribed for uremic anemia, and those may possibly exacerbate uremic gonadal damage. We studied the influences of these steroids on male gonadal function. Seventy-six hemodialysis patients were selected and examined for levels of luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone, and prolactin. Twenty-three patients who received anabolic steroids showed lower testosterone values (205.2 +/- 35.6 ng/dl) than did patients without these steroids (449.7 +/- 21.3 ng/dl). Gonadotropins and prolactin showed no significant differences between the patients with and without the steroids. The testosterone values of three patients with mepitiostane increased after they stopped taking steroids. One patient suffering from complete aspermia recovered (sperm count: 0/ml to 1300 x 10(4)/ml) after discontinuation of mepitiostane and administration of human chorionic gonadotropin (HCG). This clinical study suggests that some anabolic steroids play a role in uremic hypogonadism; thus mepitiostane or its analogues should be carefully prescribed for young male patients.