Reversible gonadotropin deficiency in male Cushing's disease.

Twelve adult males with documented active Cushing's disease were studied. Mean plasma testosterone (T) was significantly decreased: 1.8 +/- 0.3 (SEM) ng/ml (N=6.8 +/- 0.5); gonadotropin measurements in 8 patients, in basal conditions and under LH-RH iv, showed a significant decrease in both FSH and LH. A further study of 11 patients in remission of Cushing's disease indicated a significant increase in plasma T and gonadotropins up to the normal range. One patient with an initial low T value had a normalized T while in remission, then a dramatic decrease when the disease relapsed. We conclude: a hypogonadotropic hypogonadism is found in male Cushing's disease; it disappears as early as hypercortisolism is suppressed. Some possible mechanisms are discussed.