Gonadotropin-releasing hormone-dependent chorionic gonadotropin secretion in a menopausal woman.

We report the evaluation of a 46-yr-old asymptomatic menopausal woman whose serum hCG concentrations remained persistently supra-normal for 3 yr (mean +/- SD, 20 +/- 10 IU/L; n = 19). Holo-hCG and beta-core fragments were detected in the patient's urine by Ultragel chromatography, followed by specific RIAs. Trophoblastic, germ cell, and other malignancies appeared to be excluded by the absence of serum tumor markers and imaging procedures of the pelvis, abdomen, breast, and chest. Administration of a single bolus dose of synthetic GnRH (100 micrograms) increased the serum hCG concentration by 50% (from 26 to 40 IU/L). Administration of the Nal-Glu GnRH antagonist (5 mg, sc, every 12 h for 1 week) decreased the serum hCG concentration from 27 to 4.6 IU/L. The pronounced decrease in the serum hCG concentration during antagonism of the action of endogenous GnRH by administration of Nal-Glu GnRH suggests that the pituitary is the source of the supra-normal serum hCG concentrations, because the pituitary is exposed to the highest concentration of endogenous GnRH.