Journal of Clinical Endocrinology & Metabolism, Vol 45, 275-279, Copyright © 1977 by Endocrine Society

ARTICLES

Effect of bromoergocriptine on TRH-induced growth hormone and prolactin release in acromegalic patients

M Ishibashi, T Yamaji and K Kosaka

In an attempt to evaluate the dynamics of growth hormone (GH) and prolactin secretion in acromegalic patients, the response of serum GH as well as prolactin to 2-bromo-alpha-ergocriptine (CB154) alone or to CB154 combined with thyrotropin-releasing hormone (TRH) was studied in 8 subjects with this disease. Oral administration of CB154 unequivocally decreased serum prolactin levels in all of the 8 patients, while GH-inhibitory action of the drug was observed only in 6 subjects who responded to TRH with secretion of GH. The response of serum GH to TRH was not qualitatively and quantitatively altered by the treatment of patients with CB154 in a daily dose of 5 mg for two weeks. This treatment, on the other hand, remarkably suppressed basal levels of prolactin and completely blocked TRH-induced prolactin release in all of the subjects. The results suggest that there exists a dissociation between GH and prolactin responses to CB154 in acromegalic patients, and that CB154 and TRH may not share a common site of action on GH release in this pathologic state.