Suppression by thyrotropin-releasing hormone (TRH) of growth hormone release induced by arginine and insulin-induced hypoglycemia in man.

Plasma growth hormone (GH) levels were significantly increased following L-arginine (30 g) infusion or insulin (0.1 U/kg body wt)-induced hypoglycemia in normal men. When synthetic thyrotropin-releasing hormone (TRH) (1 mg) was infused intravenously for 150 min, beginning 30 min before arginine or insulin administration, GH responses to arginine and insulin were significantly blunted with a mean (+/- SE) percentage inhibition of 80.1 +/- 8.8% and 30.6 +/- 10.3%, respectively. These results suggest a possible inhibitory effect of TRH on GH secretion in man.