Combined insulin-like growth factor-1 and growth hormone improves weight loss and wound healing in burned rats

The anabolic effects of growth hormone (GH) in burned patients appear to act both directly and through insulin-like growth factor-1 (IGF-1). We, therefore, hypothesize that exogenous GH plus IGF-1 will attenuate increases in metabolism and lean muscle wasting while promoting wound healing.

Rats, each weighing 440-470 g, were given a 35% total body surface area, full-thickness scald burn and divided into four groups to receive placebo (burned controls), bovine GH (2.5 mg/kg/day), IGF-1 (2.0 mg/kg/day), or bovine GH plus rhIGF-1 (2.5 + 2.0 mg/kg/day), respectively, for 8 weeks.

Total body weight gain after 8 weeks averaged 110 g for GH plus IGF-1 compared with gains of 49 and 11 g for GH or IGF-1 alone, respectively. Burned controls lost 24 g. Metabolic rates were significantly reduced in all groups receiving growth hormones. Gastrocnemius muscle dry weight was significantly increased in those receiving GH plus IGF-1 compared with GH and IGF-1 alone or burned controls (p < .01).

Data show that GH plus IGF-1 synergistically increased lean muscle weight, total body weight, and was more effective in re-epithelialization of the burn wound than either GH or IGF-1 alone.