Gonadal dysfunction in diabetic men with organic impotence.

Previous studies of the relationship of gonadal function to impotence in men with diabetes mellitus have yielded conflicting results. Pituitary-testicular function was studied in 28 impotent diabetic men and 15 normal men. Impotence was documented by clinical history and subdivided into categories of primary organic (n = 16), primary psychogenic (n = 7), and unclassified (n = 5) on the basis of nocturnal penile tumescence (NPT) testing, psychological testing, and penile vascular studies. All NPT parameters were diminished (P less than or equal to 0.001) in the impotent diabetic men compared to values in the normal men. Endocrine studies revealed increased urinary LH (P less than or equal to 0.05) and diminished serum free testosterone levels in the diabetic men with primary organic impotence. These changes were not found in normal men or diabetic men with primary psychogenic impotence. Six months of treatment in a home blood glucose-monitoring program resulted in significant improvement in metabolic control but no improvement in pituitary-testicular function, NPT, or sexual performance in the primary organic impotent group. Eight patients with primary organic impotence and no evidence of penile vascular disease had significant improvement (P less than or equal to 0.01) in NPT results as well as subjective improvement in sexual function after 6 months of parenteral testosterone administration. These studies suggest that primary gonadal dysfunction may be related to organic impotence in diabetes, and improvement in selected patients can occur with androgen therapy.