Bromocriptine therapy in patients with acromegaly: effects on growth hormone, somatomedin A and prolactin

Six of ten patients were subjectively improved by bromocriptine treatment as illustrated by diminished sweating, reduction of soft tissue swelling and restoration of sexual potency and menstruations. These six patients had elevated or normal blood levels of prolactin, which could be stimulated by TRH and inhibited by bromocriptine. During medication two clinical responders normalized and one lowered plasma GH concentrations. Three clinical responders with initially increase somatomedin A levels normalized these levels during treatment, in one case despite lack of effect on GH levels. The four nonresponders had undetectable or notably depressed levels of prolactin, which could not be stimulated by TRH. It is suggested that the presence of prolactin, per se or as an indication of a certain dopaminergic situation, is a prerequisite for successful bromocriptine treatment of patients with acromegaly.