INSULIN-LIKE GROWTH-FACTOR-I LOWERS PROTEIN OXIDATION IN PATIENTS WITH THERMAL-INJURY

Objective The effect of insulin-like growth factor-1 (IGF-1) on energy expenditure and protein and glucose metabolism in a group of patients with thermal injury was determined. Summary Background Data Accelerat ed protein catabolism is a constant feature of the hypermetabolic resp onse to thermal injury. insulin-like growth factor-1 has been reported to minimize protein catabolism and normalize energy expenditure in an imal models of thermal injury. Methods To determine the efficacy of IG F-1 in human burn patients, resting energy expenditure (metabolic cart ), whole body protein kinetics ((N)15 Lysine), and glucose disposal (g lucose tolerance test) were assessed in eight burn patients before and after a 3-day infusion of IGF-1 (20 mu g/kg/hr). All patients were fl uid-resuscitated uneventfully and were without obvious infection at th e time of study. Enteral nutrition was administered at a constant rate before and during the IGF-1 infusion. Results Resting energy expendit ure was not altered by IGF-1 (40.3 +/- 2.2 vs. 39.1 +/- 2.3 kcal/kg/da y). However, glucose uptake was promoted, and protein oxidation decrea sed significantly (0.118 +/- 0.029 vs. 0.087 +/- 0.021 g/kg/d, p < 0.0 5) by IGF-1. In addition, insulin secretion, in response to a glucose challenge, was blunted. Conclusions Insulin-like growth factor-1 thera py has a beneficial effect in preserving lean body mass during severe stress conditions by minimizing the flux of amino acids toward oxidati on.