Serum Glucagon after Arginine Infusion in Aged and Young Subjects

In 12 aged nondiabetic subjects, 10 aged diabetic subjects, and 6 young nondiabetic subjects the glucose, insulin, glucagon and growth hormone responses to the intravenous administration of arginine were studied. A prompt increase in the levels of blood glucose, serum insulin and serum glucagon was observed, but the glucose and glucagon peaks were significantly higher in the aged nondiabetic and diabetic subjects. Growth hormone secretion did not differ between the nondiabetic aged and young subjects. These findings suggest the hypothesis that glucose intolerance in old age is due to increased release of glucagon.