Role of testosterone and dihydrotestosterone in spontaneous gynecomastia of adolescents.

To test a possible hormonal mechanism of gynecomastia at puberty, a group of pubertal spontaneous gynecomastia (PSG) and healthy young volunteers (HYV), Tanner's stage II-V, were studied. Peripheral blood samples were obtained for measuring follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), testosterone (T), dihydrotestosterone (DHT), estradiol (E-2) and estrone (E-1). No difference was established in steroids in pituitary hormonal concentration when both groups were compared on a sexual stage-matched control basis, except for T 2 SD in 5/9 subjects of PSG and DHT 2 SD in all of PSG. The T:DHT ratio varied from 5.0 to 15.4 in PSG and from 0.42 to 2.224 in HYV. Whether spontaneous gynecomastia might exist in an enzimatic blockade of 5 alpha-reductase and whether a decrease in the T:DHT ratio might favor the estrogen action for the progression of breast enlargement deserve further analysis.