A rationale for the use of bromocriptine in patients with amenorrhea and normoprolactinemia.

The return of menses in amenorrheic normoprolactinemic women after treatment with bromocriptine is well documented. To determine whether an increased pituitary prolactin-secreting capacity may be the underlying mechanism, 14 women with amenorrhea were studied. None complained of galactorrhea, but in all 14 it was possible to express a few drops of milk from the nipple. All women were normoprolactinemic and had normal sellar tomography. A standard thyrotropin-releasing hormone (TRH) test was performed and bromocriptine (2.5 mg twice daily) was administered. Within 8 weeks, 9 of 14 patients had return of menses. The second group of five patients did not respond to bromocriptine. The mean prolactin response to TRH was significantly greater in those women who experienced return of menses, although there was individual overlap between both groups. This finding suggests that enhanced prolactin secretory capacity may account for amenorrhea is some apparently normoprolactinemic patients. The TRH test may serve to identify those patients who may benefit from bromocriptine.