Response of amenorrheic patients with normal serum prolactin to chlorpromazine during administration of human menopausal gonadotropin

To study the effects of graded amounts of estrogens on prolactin (PRL) secretion, PRL response to chlorpromazine (CPZ) during administration of human menopausal gonadotropin (hMG) was determined. A control CPZ test was done prior to initiation of hMG therapy and the test was repeated when endogenous estrogen secretion reached the physiologic range (350 to 400 pg. per milliliter) which stimulates luteinizing hormone surge in the normal ovulatory menstrual cycle. Six euprolactinemic women with secondary amenorrhea were studied. Studies showed that there was no significant change in the mean serum prolactin concentrations during control and repeat CPZ testing procedure (5.8 ± 2 and 10.8 ± 2 ng. per milliliter, p < 0.1). The maximal response of PRL to CPZ was significantly higher during hMG-induced high estrogenic state than during control testing (69.9 and 32.3 ng. per milliliter, p < 0.01). This finding suggests that endogenous estrogen may play a role in the regulation of serum prolactin concentration during the menstrual cycle.