Testicular steroidogenic response to human chorionic gonadotropin of fifteen male transsexuals on chronic estrogen treatment.

Fifteen transsexuals were prepared for surgery with estrogen treatment. The response to human chorionic gonadotropin (hCG) in the untreated state was similar to that of normal subjects when testosterone (T), estradiol-17 beta (E2), 17 alpha-hydroxyprogesterone (17 alpha-OHP), progesterone (P), 4-androstenedione (delta 4A), and dehydroepiandrosterone (DHA) were used as indices. Following estrogen therapy, plasma T, 17 alpha-OHP, and DHA levels were markedly reduced whereas delta 4A and P were not. In spite of the suppressive effects of estrogen, a good response to hCG was noted in such subjects in plasma levels of T, 17 alpha-OHP, and, to a lesser extent, delta 4A even after estrogen administration for 24 months. The high rates of 17 alpha-OHP to T induced by estrogen treatment is restored to normal by the administration of hCG.