Local effect of burn injury on glucose and amino acid metabolism by skeletal muscle.

Previous studies from our laboratory demonstrated that there is a difference in glucose metabolism by skeletal muscles from the burned versus unburned regions of the body. To further investigate the effect of proximity to the burn wound on muscle metabolism, in vitro glucose uptake as well as lactic and amino acid releases by soleus muscles, were studied 3 days following a 3-second scald burn on one hind limb of the rat. No differences in glucose uptake or lactic and amino acid releases were observed between soleus from the unburned limb of burned rats and that of controls. In comparison to these two groups, soleus from the burned limb took up 125% more glucose (p less than 0.001), and released 80% more lactic acid (p less than 0.01), 229% more alanine (p less than 0.001), 84% more glutamic acid (p less than 0.01), and over 36% more glutamine (p less than 0.05). The relatively enhanced release of lactic acid by soleus muscle from the burned limb was reduced but not eliminated by the omission of glucose from the medium. Simultaneously, the omission of glucose had no effect on the release of alanine, glutamic acid, and glutamine by the burned limb soleus. The data indicate that a mild thermal injury stimulates glucose utilization and enhances amino acid release by skeletal muscle from the burned region. Since such an effect is absent in muscle from the contralateral unburned region of the same animal, the changes are not likely to be mediated by systemic alterations in the metabolic and endocrine environment. The persistence of an enhanced amino acid release in the presence of varying glycolytic rates suggests that the burn-induced local alterations in amino acid metabolism by skeleton muscle are independent of coincident changes in glucose utilization.