Suppressibility of glucagon secretion by glucose in juvenile diabetes.

The suppressibility of plasma glucagon concentrations by glucose was investigated in normal and diabetic children. Fasting concentrations of plasma glucagon were similar in normal and in diabetic children despite the hyperglycemia of the latter. Infusion of glucose promptly suppressed glucagon values in the normal as well as in the diabetic children pretreated with half of their usual morning dose of insulin. Glucose alone, however, did not suppress plasma glucagon in diabetic patients, despite the attainment of significant hyperglycemia. Administration of insulin during an ongoing glucose infusion in the diabetic patients lowered their blood glucose concentration; the concentration of glucagon rose transiently when the glucose concentration fell. These data confirm the existence of relative hyperglucagonemia inappropriate for the degree of blood glucose concentration in diabetic children deprived of insulin. The data also suggest that this hyperglucagonemia is secondary to insulin deficiency and suppressibility of glucagon by glucose can be restored by insulin therapy.