Regulation of glucose kinetics in trauma patients by insulin and glucagon

The current study was undertaken to evaluate the contribution of insulin and glucagon to regulation of glucose metabolism in man following severe, traumatic injury by manipulating concentrations of insulin and glucagon with infusions of somatostatin. Glucose kinetics were assessed with [U-14C, 6-(3)H]glucose in severely injured patients and compared with data obtained from patients recovering from minor, elective operative procedures. Glucose production was significantly increased in subjects with traumatic injury compared with control subjects (13.0 +/- 0.63 mumol/kg/min v 8.6 +/- 0.27 mumol/kg/min). There was no impairment in glucose oxidation by the injured patients. Modulation of insulin and glucagon with somatostatin indicated that non-insulin-mediated glucose uptake (NIMGU) was significantly elevated in injured patients (12.2 +/- 0.94 mumol/kg/min v 7.4 +/- 0.61 mumol/kg/min). Hepatic glucose output (HGO) in the absence of glucagon was also significantly elevated in injured patients (12.2 +/- 1.20 mumol/kg/min v 5.8 +/- 1.08 mumol/kg/min). Indirect calorimetry showed a 27% increase in resting energy expenditure (REE). Increased protein oxidation accounted for 56% of the increase in REE. Changes in carbohydrate and lipid oxidation accounted for 28% and 15% of the increase in REE. There was no correlation between the injury severity score of the injured patient and the degree of metabolic abnormality. It is concluded from these studies that (1) injured patients have a high rate of glucose turnover in the absence of glucagon and insulin; (2) the reliance on glucose as a source of energy is not diminished in injured subjects; and (3) increases in protein oxidation account for the majority of the increased REE found in injured patients.