A submaximal dose of insulin promotes net skeletal muscle protein synthesis in patients with severe burns

Objective: To investigate the hypothesis that a submaximal insulin dose reverses the net muscle catabolism associated with severe burns, and to determine its effects on amino acid kinetics. Summary Background Data: The authors previously showed that a maximal dose of insulin administered to patients with severe burns promoted skeletal muscle glucose uptake and net protein synthesis. However, this treatment was associated with caloric overload resulting from the large quantities of exogenous glucose required to maintain euglycemia, and hypoglycemia was a potential problem. Methods: Thirteen patients were studied after severe burn injury (>60% total body surface area). Patients were randomly treated by standard care (n = 5) or with exogenous insulin (n = 8). Data were derived from an arteriovenous model with primed-continuous infusions of stable isotopes and biopsies of the vastus lateralis muscle. Results: Net amino acid balance was significantly improved with insulin treatment. Skeletal muscle protein synthesis was significantly greater in the group receiving insulin, whereas muscle protein breakdown was not different between the groups. This submaximal dose of insulin did not affect glucose or amino acid uptake or require a greater caloric intake to avoid hypoglycemia. Conclusions: Submaximal insulin can promote muscle anabolism without eliciting a hypoglycemic response.