Endocrine diagnosis of pituitary tumor in galactorrhea syndromes

Endocrine aspects of 17 patients with inappropriate galactorrhea were evaluated. Six of the patients had radiographic evidence of pituitary tumor, and in two, on whom operation was performed, chromophobe adenoma was found. All patients suspected of having tumors had normal thyroid and adrenal function, and only one did not respond fully to metyrapone. Hypothyroidism and Cushing's syndrome were presumed causes of galactorrhea found among the "nontumor" group. All the "tumor" patients and three of the "nontumor" group had marginal or subnormal growth hormone responses to arginine. Serum luteinizing hormone (LH) levels displayed marked variability in both categories of patients. A sequence of gonadotropin loss secondary to tumor compression is suggested in which follicle-stimulating hormone is diminished prior to LH. The future usefulness of exogenous testing with l-dopa and synthetic LRF in galactorrheic syndromes is cited.