Biphasic alterations in glucose metabolism by soleus muscle from the burned limb

Tissue temperature and in vitro glucose metabolism by rat soleus muscle were studied following a 3-second burn on one hind limb in 90 degrees C water. The injury increased the subcutaneous temperature in the calf of the burned limb to 53.4 +/- 0.7 (SE) degrees C and that between soleus muscle and fibula to 49.4 +/- 1.3 degrees C, both temperatures returning to normal at approximately 3 minutes postburn. The injury resulted in biphasic alterations in glucose metabolism by the soleus muscle from the burned limb; glucose uptake and lactate release were depressed at 4 hours but were elevated above control levels at 3 days postburn. The maintenance of an approximate 1:2 ratio of glucose uptake to lactate release suggested that changes in glucose uptake reflected primarily conversion to tricarbon units rather than changes in the rate of glucose oxidation. Since glucose metabolism by soleus muscle from contralateral unburned limb of injured animals did not differ from controls at any of the test times, the changes in the burned limb were not likely the result of systemic alterations in metabolic and endocrine environment. The biphasic alterations did not correlate with the degree of soleus muscle edema. It is concluded that proximity to the burn wound is a new determinant of abnormal glucose utilization by skeletal muscle.