Sulpiride stimulation of prolactin secretion in adolescents with gynecomastia: relation to the circulating levels of estradiol.

Basal levels of prolactin (PRL) and estradiol (E2) were studied in 10 adolescents with gynecomastia who were at stages II to IV of their sexual development. In 7 of the 10 patients, the hypophyseal response of PRL to the administration of sulpiride was assessed: 5 of the 7 received 25 mg i.m., and the remaining 50 mg. i.m. The 10 cases were compared with 12 control boys without gynecomastia matched for stage of sexual development. Five of the controls were given 25 mg of sulpiride i.m. and the other 50 mg. Basal PRL levels were the same in both groups. Sulpiride stimulates the secretion of PRL in boys with and without gynecomastia. However, a significantly increased circulating E2 level was found in patients with gynecomastia