Glucagon-initiated human growth hormone release: a comparative study.

Human growth hormone (HGH) responses in 20 healthy adults to subcutaneous glucagon, arginine infusion and tolbutamide and insulin hypoglycemia were compared. HGH rose in all four tests. HGH response to glucagon was also studied in 49 patients with suspected pituitary insufficiency, of whom 25 also later received an arginine infusion; an abnormal response to glucagon was the most frequent functional abnormality and often HGH was the only anterior pituitary hormone of which a deficiency was detectable. In seven subjects (two healthy controls and five patients with suspected hypopituitarism) there was a subnormal HGH response to arginine but a normal response to glucagon. It is concluded that glucagon is a simple and effective stimulus to HGH release, equal or superior to arginine, tolbutamide and insulin, and is an important test of anterior pituitary function.