Metergoline, a potent serotonin antagonist, has proved to be effective in the treatment of hyperprolactinemic anovulation. On the other hand, some investigators have reported that bromocriptine, a potent dopamine agonist, is effective in the treatment of normoprolactinemic anovulation as well as hyperprolactinemic anovulation. But there are very few reports as to whether metergoline is effective or not in the treatment of normoprolactinemic anovulation. This study was designed to investigate

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... ovulation-inducing effect and the underlying mechanism of metergoline in women with normoprolactinemic anovulation . Metergoline was administered 8-12 mg daily for 8 2 weeks to 28 patients without galactorrhea (7 cases with anovulatory cycle, 17 cases with 1st grade amenorrhea defined by responding to progestin with bleeding, and 4 cases with 2nd grade amenorrhea defined by responding to estrogen and progestin with bleeding), whose serum prolactin levels were under 25 ng/ml. The serum levels of LH, FSH and prolactin, and also the pituitary responsiveness to 100 lig of LH-RH and 500 lig of TRH were examined before and during metergoline administration in 13 amenorrheic patients. In patients whose ovulation or withdrawal bleeding was induced and in patients whose menstruation was not induced , these stimulation tests during metergoline administration were performed at 5 7 days from the onset of menstruation and between 6 and 8 weeks from the beginning of treatment, respectively. In 6 other amenorrheic patients, the positive feedback effect of estrogen (Premarin 20 mg iv) on LH release was examined before and during treatment. In addition, a 12 mg dose of metergoline was administered daily for one menstrual cycle to 5 normal cycling women , and the Premarin stimulation tests were performed before and after metergoline treatment.