[Evaluation of dynamic pituitary function testing in patients with hyperprolactinemia on diagnosis of pituitary prolactin-secreting adenoma (author's transl)].

Thirty hyperprolactinemic women were divided into four group according to radiological and computed tomographic findings of sella turcica as follows; sulpiride-induced (N = 7), functional (N = 6), microadenoma (N = 9) and macroadenoma (N = 8). It was measured the serum basal level of pituitary LH, FSH, PRL, TSH and GH, and the responsiveness to LH-RH, TRH, insulin administration, respectively. These values were compared to that during bromocriptine treatment (5mg/day, 2 weeks). Before and during treatment with bromocriptine, there were not significant changes of basal level of LH, FSH and TSH, and also the responsiveness to LH-RH administration in four group. In pretreatment period, PRL responsiveness to TRH was good in sulpiride-induced and functional groups, but decreased in microadenoma and macroadenoma groups. During bromocriptine treatment period, basal PRL level was significantly suppressed in three groups except sulpiride-induced group, and PRL responsiveness to TRH was good in three groups except macroadenoma group. These findings ae concluded as follows: 1) Mechanism of the disturbance of ovulation in hyperprolactinemia does not closely related to pituitary gonadotroph dysfunction. 2) Decreased PRL responsiveness to TRH (maximal fold increase: under 40%) is of diagnostic value of pituitary adenomas. 3) Difference of PRL responsiveness to TRH during treatment with bromocriptine is distinguishing the microadenoma from macroadenoma.