Effects of estrogen on the release of gonadotropins and prolactin in male pseudohermaphrodites

Three adult patients with male pseudohermaphroditism were given 15 μg/kg body weight of 17 β-estradiol im daily (at 08:00 hours) for 12–15 days and circulating levels of gonadotropins, prolactin and estradiol were determined by radioimmunoassay before and during the steroid course. All patients had elevated gonadotropin levels prior to starting on estradiol. During estrogen treatment all patients demonstrated suppression of FSH and LH with a subsequent rise in LH (positive feedback) while estrogen levels remained elevated. A similar positive feedback effect on the secretion of FSH could not be demonstrated. In two patients, who had never received estrogen treatment prior to this study, estradiol induced a significant elevation of serum prolactin levels within 24 h and levels remained higher than basal values for the rest of the estrogen treatment period. In the third patient, who had been previously treated with estrogen, serum prolactin levels did not change significantly during estrogen treatment. This study has afforded evidence for the presence in humans of an estrogen mediated LH release concomitant with an augmented prolactin secretion.