Amino acid metabolism in patients with severe burns.

In this study we set out to determine, if relative to net catabolism of skeletal muscle protein as measured by phenylalanine release, the transamination of branched-chain amino acids (valine, isoleucine, and leucine) was greater in nonseptic burn patients than in controls. Arterial and femoral venous amino acid concentrations and circulating liver enzyme levels were measured. When the ratio of the arterial-femoral venous difference in concentration of each branched-chain amino acid to that of phenylalanine was determined, transamination of the branched chain amino acids, relative to net proteolysis, was not occurring at a greater rate in the burn patients. The net release of alanine relative to that of phenylalanine was not significantly greater in the burn patients, consistent with the conclusion that relative to the net rat of proteolysis, transamination of branched-chain amino acids in skeletal muscle is not increased in burn patients. This finding differs from that in septic dogs and septic humans. The mean arterial-femoral venous differences in concentration of alanine, valine, isoleucine, leucine, and phenylalanine were greater in the burn patients (P less than 0.03), indicating increased proteolysis in this group.