Journal of Clinical Endocrinology & Metabolism, Vol 41, 176-179, Copyright © 1975 by Endocrine Society

ARTICLES

Effect of synthetic gonadotropin-releasing hormone (GnRH) in a patient with the "fertile eunuch" syndrome

C Williams, RG Wieland, EM Zorn and MC Hallberg

A patient with isolated LH deficiency ("fertile eunuch" syndrome) was given synthetic gonadotropin releasing hormone (GnRH) by a single intravenous injection and serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone and dihydrotestosterone were measured. A significant rise in both gonadotropins was found after GnRH and the increase was similar to that reported for normal men. No significant change was noted in the serum androgen levels. The patient was re-tested with another single intravenous injection after a 6-h infusion of GnRH two days later. The rise in serum Fsh and LH levels during the infusion was greater than with the initial bolus. A further increase in LH but not FSH concentration was noted when a 150 mug bolus was given at the end of the infusion. Acute (4 day) treatment with human chorionic gonadotropin (hCG) resulted in an increase in the serum testosterone and dihydrotestosterone levels to those observed in normal adult males. The "fertile eunuch" syndrome thus appears to be a hypothalamic disorder. It is consistent with the concept of more than one hypothalamic factor controlling gonadotropin secretion. Other possibilities would be deficient or defective production of a releasing factor affecting one or both gonadotropins. The lack of a definite response of serum androgens to GnRH would appear to be secondary to a decreased number of differentiated Leyding cells.