Abstract
The synthetic growth-hormone-release inhibitory hormone (G.R.-I.H.) inhibits G.H. response to insulin-induced hypoglycæmia without affecting the prolactin or corticosteroid responses, but the effects are short-lived. The normal thyrotrophin and follicle-stimulating hormone (F.S.H.) responses to thyrotrophin-releasing hormone (T.R.H.) were impaired by G.R.-I.H., although the prolactin response was unaffected. G.R.-I.H. did not alter luteinising hormone (L.H.) or F.S.H basally or after L.H/F.S.H releasing hormone. Circulating G.H. levels fell strikingly in three acromegalic patients given G.R.-I.H. infusion, but their prolactin levels were not affected. G.R.-I.H. holds great promise for the medical treatment of diseases associated with excess G.H. secretion such as acromegaly, gigantism, and diabetes mellitus.