Chlorpromazine Treatment and Growth Hormone Secretory Responses in Acromegaly

Abstract

Eight patients with active acromegaly were treated with 100–200 mg chlorpromazine (CPZ) daily for 3 to 6 months. Clinical improvement did not occur in any patient. Mean basal growth hormone (MBGH) levels decreased substantially in only one patient in whom the MBGH fell from 94.3 ng/ml to 56.3 ng/ml after one month of therapy; further reduction in the MBGH did not occur in spite of continued treatment and doubling of the initial dose of CPZ. The MBGH increased in three patients during therapy. Oral glucose tolerance tests were performed before and during treatment in all patients; insulin and arginine tolerance tests were performed before and during therapy in six patients. Patterns of growth hormone (GH) secretion following administration of glucose, insulin, and arginine were highly variable in individual patients before and throughout treatment. Our data are consistent with the hypothesis that GH secretion is not truly autonomous in most patients with aeromegaly.