Intracellular enzymes and protein synthesis in rabbit skin after thermal injury.

1. The concentrations of several intracellular enzymes in rabbit skin have been measured 5 min, 2, 6 and 24 h after thermal injury.2. At 5 min and 2 h after a burn (60 degrees C for 1 min) there was a significant fall in the enzyme activities whereas at 6 h their activities were higher than control.3. It appears that the increase in enzyme concentrations in the lymph during the first few hours after thermal injury is associated with a fall in the enzyme concentrations in the tissues and therefore might be the result of leakage of enzyme from storage sites in the injured cells.4. The second increase in enzyme concentrations in the lymph which has been observed 6-18 h after thermal injury occurs at a time when there is also an increase in the enzyme concentrations in the tissue.5. It seems unlikely that these increased activities are due to new synthesis since there was no apparent correlation between tissue enzyme concentrations and protein synthetic activity, and the changes still occurred after administration of cycloheximide.6. There was a change in the LDH isoenzyme pattern after injury towards a predominance of LDH-1. This change did not occur immediately after the burn, but was present at 2 and 6 h, and returned to normal 24 h later.