Effect of hemorrhagic shock, fasting, and corticosterone administration on leucine oxidation and incorporation into protein by skeletal muscle

The metabolism of leucine by rabbit skeletal muscle was studied 1 and 3 days after shock or glucocorticoid administration. Hemorrhagic shock resulted in an increase in the capacity for leucine oxidation and a concomitant suppression of leucine incorporation into protein by skeletal muscle. This defect persisted, in part, for at least 3 days following injury. Corticosterone administration to normal animals produced an increase in leucine oxidation and a decrease in leucine incorporation into protein similar to that observed following shock. Fasting, in contrast, caused a simultaneous decrease in both leucine oxidation and incorporation into protein. These findings are consistent with the possibility that the net protein catabolism associated with hemorrhagic shock may be promoted by removal of leucine from the cellular protein synthetic amino acid pool through irreversible combustion. Shock-induced adrenal steroid secretion may contribute to the observed changes in leucine metabolism by skeletal muscle.