The influence of the prolactin inhibitor bromocriptin (CB 154) on human luteal function in vivo

Five volunteers with normal ovarian cycles received oral doses of 2 X 2.5 mg or 3 X 2.5 mg bromocriptin (CB 154)/day respectively. The treatment started at the onset of menstruation and lasted on complete cycle. In addition to the decrease of prolactin secretion, a reduction of plasma progesterone concentrations during the corpus luteum phase was demonstrated. This fall of progesterone seemed to be preferentially due to bromocriptin-induced hypoprolactinaemia and not to direct ovarian effects of the drug.