Prolactin dynamics in a patient with isolated ACTH deficiency accompanied by hyperprolactinemia.

Case of isolated ACTH deficiency accompanied by hyperprolactinemia was reported. Prolactin (PRL) secretory dynamics were evaluated by several stimulation (thyrotropin-releasing hormone [TRH], sulpiride) and suppression (L-dopa) tests. Before glucocorticoid replacement therapy, both TRH and sulpiride administration resulted in PRL hyper-responsiveness. The sulpiride-induced PRL increase was higher than that induced by TRH. L-dopa administration resulted in normal PRL suppression. Following glucocorticoid replacement therapy, the elevated basal PRL level returned to normal, and PRL hyper-responsiveness to TRH or sulpiride also returned to normal. These data suggest that the elevation of basal PRL level and PRL hyper-responsiveness observed in this patient is caused by glucocorticoid deficiency.