Endocrinologic evaluation of impotence.

Among 600 impotent men who had endocrine evaluation for androgen deficiency, thyroid deficiency, and hyperprolactinemia, 192 (32%) were found to have an endocrine abnormality. Androgen deficiency was divided into primary testicular failure and "hypothalamic-pituitary dysfunction" by an androgen quotient derived using simultaneous gonadotropin and testosterone levels. This androgen quotient was found to correlate well with the response to testosterone and was more useful than the testosterone level in predicting which patients would benefit from long-term testosterone replacement. Unsuspected hypothyroidism (6%) and hyperprolactinemia (3%) were both common in this group of patients, and appropriate treatment reversed the impotence.