Impaired steroidogenic function of corpora lutea from hyperprolactinemic baboons induced by sulpiride

It has been noticed that hyperprolactinemia can cause luteal insufficiency as well as anovulation in women. In order to explore the mechanism underlying this disorder, hyperprolactinemia was induced in baboons (Papio cynocephalus) by daily administration of sulpiride during follicular and early luteal phases. In hyperprolactinemic baboons, the plasma progesterone level was suppressed without notable changes in plasma estradiol, LH and FSH levels. When corpora lutea from these baboons were examined in vitro to investigate their ability to convert 14C-pregnenolone into various steroids, there was progressive inhibition of steroid metabolism related to the plasma levels of prolactin. These findings strongly suggest, although do not actually prove, that an elevated level of prolactin could directly impair luteal function by adversely affecting 3 beta-hydroxysteroid dehydrogenase activity.