ENHANCED AMINO-ACID-UPTAKE IN BOTH SKELETAL-MUSCLE AND LIVER BY BURN PLASMA IN RATS

The study was designed to test amino acid uptake in skeletal muscle af ter burn injury (up to 72 h). Also examined were the effects of plasma from burned rats over varying periods postburn (1-72 h), when plasma was added in vitro to incubated muscles and liver slices. Major burn i njury (40 per cent total body surface area (TBSA)) was produced in mal e Sprague-Dawley rats weighing 60-80 g. Both soleus muscles were disse cted intact at 1, 3, 6, 12, 24, 48 and 72 h postburn. Amino acid trans port was measured by determining intracellular uptake of [H-3] alpha-a minoisobutyric acid (AIB) during a 2 h incubation. In the second serie s of experiments, whole plasma from burned rats was added in vitro to incubated muscles and liver slices from healthy animals, and amino aci d uptake was determined. AIB uptake in burned rat muscle was reduced b y 24 per cent by 24 h postburn and 16 per cent by 48 h postburn. There was an increased effect from burn plasma on normal incubated muscles and liver slices, 72 per cent on muscles and 30 per cent on livers. Pr esent results suggest an intrinsic decrease in amino acid uptake by mu scle from burned rats. A factor or factors existed in plasma which inc reased both muscle and liver amino acid uptake postburn.