Objective: The study clarified the effects of growth hormone treatment on forearm amino acid efflux in patients with full nutritional support after gastrointestinal surgery.
Summary background data: Growth hormone attenuates net nitrogen loss after surgical trauma. An increase in net protein synthesis has been described, whereas the results regarding protein breakdown have been conflicting.
Methods: Elective patients undergoing abdominal surgery were double blindly randomized to treatment with recombinant human growth hormone (GH, n = 9) 24 IU or placebo (PL, n = 10) the first 5 postoperative days. All received parenteral nutrition (nitrogen = 5.7 +/- .1 g/m2, energy = 1018 +/- 12 kcal/m2 (125 +/- .7% of BMR) and epidural analgesia. Amino acid plasma levels and forearm fluxes were measured.
Results: The second postoperative day, growth hormone abolished forearm efflux of total amino acid nitrogen (GH: 170 +/- 117, PL: -785 +/- 192 nmol/100 mL/min, p = .0007) due to reduced losses of both essential and nonessential amino acids. Glutamine release was abolished (13 +/- 15 vs. -137 +/- 43 nmol/100 mL/min, p = .007) and alanine release attenuated (-61 +/- 17 vs. -211 +/- 51 nmol/100 mL/min, p = .01). 3-Methyl-histidine release was attenuated (-.20 +/- .11 vs. -.62 +/- .09 nmol/100 mL/min, p = .04). Growth hormone also induced decreased venous plasma amino acid levels.
Conclusions: When given after gastrointestinal surgery in patients treated with total parenteral nutrition, growth hormone treatment abolished glutamine, 3-methylhistidine, and total amino acid nitrogen loss from forearm tissue. Alanine loss from forearm tissue was attenuated.