Role of insulin and glucagon in the response of glucose and alanine kinetics in burn-injured patients

Abstract

We investigated the roles of insulin and glucagon as mediators of changes in glucose and alanine kinetics during the hypermetabolic response to injury in 10 burn patients by infusing somatostatin with and without insulin replacement. Glucose and alanine kinetics were measured by primed-constant infusions of 6,6-d2-glucose and [3-13C]alanine. The basal rate of glucose production and alanine flux were significantly elevated in all patients. Lowering both hormones simultaneously caused an insignificant reduction in glucose production, but plasma glucose rose significantly (P < 0.01), because of reduced clearance. Alanine flux and total plasma amino nitrogen increased significantly (P < 0.05) above basal. Selectively lowering glucagon concentration decreased glucose production (P < 0.05), and exogenous glucose was infused to maintain euglycemia. Alanine flux and total plasma amino nitrogen remained unchanged. In severely burned patients (a) hyperglucagonemia stimulates increased glucose production, (b) basal insulin suppression glucose production, stimulates basal glucose clearance, and is important for regulation of plasma amino acid concentrations, and (c) the selective lowering of glucagon while maintaining basal insulin constant normalized glucose kinetics.