Effect of exogenous growth hormone on glucose utilization in burn patients

The treatment of burn patients with recombinantly derived human growth hormone (rHGH) appears effective in counteracting protein catabolism. However, exogenous growth hormone is frequently associated with hyperglycemia, an aspect which may limit its usefulness. Therefore, to assess the affect of rHGH on glucose utilization, 13 severely burned patients (65% ± 4 TBSA burn; mean ± SEM) began receiving on admission either placebo or rHGH (0.2 mg/kg.d) in a double-blind randomized fashion. While hypermetabolic (percentage REE/predicted REE 1.41 ± 0.11) fasting oxygen consumption and CO₂ production were measured using indirect calorimetry prior to and then during a hyperinsulinemic euglycemic clamp. This experiment demonstrated that rHGH significantly reduced glucose uptake and inhibited glucose oxidation compared to the placebo patients. Since the decreases in glucose oxidation and uptake were proportional, glucose utilization (percentage glucose uptake oxidized) remained similar in both patient groups. Furthermore, the hyperinsulinemic clamp lowered the plasma amino acid concentrations in the control patients while rHGH-treated patients had no significant alterations. In conclusion, exogenous growth hormone therapy induces an insulin resistance in burn patients. Furthermore, since the glucose utilization did not change, it is likely that the mechanism of insulin resistance is due to a deficiency in glucose transport.