[Correlation of prolactin-secreting-capacity to circadian profile of prolactin in euprolactinemic women with ovulatory disturbances].

Circadian profile and responsiveness of prolactin to TRH administration were examined in 21 women with ovulatory disturbances. The data were analyzed with reference to the clinical effectiveness of bromocriptine administration. Resting levels of serum prolactin in the patients studied were lower than 25 ng/ml. 14 patients out of 16 cases (Group A) responded to bromocriptine, whose prolactin levels were more than 30 ng/ml during the night in the circadian studies. On the other hand, none of 5 patient (group B) responded to bromocriptine, whose prolactin levels were not more than 30 ng/ml during the night. Group A showed hyper-responsiveness of prolactin to TRH higher than that of Group B. These results suggested that 1) In euprolactinemic ovulatory disturbances there are cases with nocturnal hyperprolactinemia, whose prolactin levels are normal during the day time. These cases will be referred to as occult hyperprolactinemia. 2) Those with occult hyperprolactinemia show increased prolactin-secreting-capacity, which is able to be diagnosed by the hyper-responsiveness of prolactin to TRH administration. 3) The effectiveness of bromocriptine in treating euprolactinemic ovulatory disturbances is due to the suppressive effect of bromocriptine on the hyperprolactinemic states of occult hyperprolactinemia.