Prolactin secretion and gynecomastia

Nine males with gynecomastia were examined. The serum levels of LH, FSH, prolactin, testosteron, estradiol were determined, in some of the patients--progesteron. A stimulation with thyreoliberin was carried out to follow up prolactin reaction. The same examinations were performed with a control group of healthy males. Contrary to the healthy subjects, the patients with gynecomastia had a significantly higher levels of FSH and progesteron and testosteron was reduced with statistical significance. The basal level of prolactin in the patients with gynecomastia was not significantly increased and no deviations in the parameters of prolactin reaction was observed after the stimulation by thyreoliberin. On the base of those results progesteron in the males with gynecomastia is admitted to be able to support the mammo--tropic effect of estrogens, together with the reduced androgens and the altered receptivity of the mammary glands. Prolactin is of no great importance for gynecomastia.