ENHANCEMENT OF PROTEIN-SYNTHESIS EFFICIENCY IN PARENTERALLY FED TRAUMA VICTIMS BY ADJUVANT RECOMBINANT HUMAN GROWTH-HORMONE

In the early catabolic phase of severe injury, conventional nutritional support is inadequate to reverse negative nitrogen balance and an anabolic stimulus may be beneficial. The utilization efficiency of body energy sources after injury could be improved by adjuvant recombinant human growth hormone (rhGH) therapy. We measured the protein kinetic response to exogenous rhGH in trauma patients fed parenterally (TPN). Severely injured (mean ISS, 31 +/- 2), highly catabolic (mean nitrogen loss, 19 +/- 2 g/day), and hypermetabolic (mean BEE/REE, 1.41 +/- 0.05), adult (mean age, 46 +/- 5 years), multiple trauma victims (n = 20, 17 men/3 women) were investigated. Rates of whole-body protein kinetics (turnover [WBPT], synthesis [WBPS], breakdown [WBPB], and protein synthesis efficiency [PSE]-the fraction of nitrogen turnover utilized for protein synthesis) were measured using a primed-constant infusion of N-18 glycine 48 to 60 hours after injury when the patients were receiving only maintenance fluids without calories or nitrogen. The patients were then fed glucose-based TPN (1.1 x REE; 250 mg N/kg/day) and randomized to receive or not to receive rhGH. Group H (n = 10) received daily rhGH (0.15 mg/kg/day, Somatropin, Genentech, Inc.) intramuscularly at 8 Am and group C (n = 10) received only the vehicle of infusion. Protein kinetic measurements were repeated at the end of 7 days. In group H after 7 days of TPN (a) nitrogen balance was less negative (-41 +/- 18 vs. -121 +/- 19 mg N/kg/day); (b) protein synthesis efficiency was higher (62 +/- 2.2% vs. 48.0 +/- 3%); (c) whole-body protein synthesis rate was 28 +/- 2% higher; and (d) deficient (because of trauma) anabolic growth hormone, IGF-1, and insulin levels were significantly elevated. We conclude that adjuvant rhGH promotes protein anabolism in parenterally fed trauma victims that may be useful in promoting repair and early recovery.