LOCAL EFFECT OF THERMAL-INJURY ON SKELETAL-MUSCLE BLOOD-FLOW AND NUCLEOTIDE LEVELS

Abstract

Three days following a 3-s scald of 1 hind limb, in vitro glucose utilization was markedly increased in soleus muscle from the burned limb but not in soleus from the contralateral unburned limb. Factors that might contribute to this local metabolic alteration were studied. Three days following a 3-s scald of 1 hind limb of the rat, blood flow through soleus and gastrocnemius muscles of the burned limb as measured with labeled microspheres was increased 167% (P < 0.01) and 58% (P < 0.04), respectively. Calf muscles of the burned limb, frozen in situ, showed a 48% decrease in ATP (P < 0.001), 37% decrease in ADP (P < 0.001), 192% increase in AMP (P < 0.01), 45% decrease in total adenine nucleotides (P < 0.001), 132% increase in pyruvate (P < 0.001) and 377% increase in lactate (P < 0.001). Blood flow and ATP, ADP, total nucleotides and pyruvate levels of calf muscles of unburned limb of burned rats did not differ from controls, but AMP and lactate were increased 115% (P < 0.05) and 144% (P < 0.001), respectively. The decrease in ATP and increase in AMP and lactate in muscles of the burned limb suggest an increased rate of glycolysis in vivo which may be due partly to the stimulation of phosphofructokinase. The increased AMP and lactate may contribute to the increase in blood flow in muscles of the burned limb. Thermal injury apparently alters local adenine nucleotide levels, which results in elevated glucose utilization and blood flow in muscles of the burned region.