Changes in plasma levels of lysosomal and non lysosomal enzymes during hemorrhagic hypotension

In a study of 4-hr hemorrhagic hypotension in dogs, the plasma levels of the lysosomal enzymes, cathepsin (CATH) and acid phosphatase (AP) showed early and progressive increases in activity. The plasma levels of the intestinal fraction of alkaline phosphatase (IAkP) and aspartate aminotransferase (AAT) were increased after 2 hr of hypotension and the liver specific enzyme, ornithine carbamyltransferase (OCT), and creatine phosphokinase (CPK), after 3 hr. All of the enzymes showed large increases after 4 hr of hypotension. The plasma levels of CATH showed the earliest and largest relative increase indicating that with the shock model used, this enzyme was the most sensitive indicator of shock severity. The increase in plasma enzyme levels was probably the result of tissue damage in the splanchnic region but the elevation of plasma CPK, a muscle specific enzyme, indicates some muscle cell damage as well. While the increase in the plasma enzyme activity is probably due, in large part, to cellular damage, it is likely that a decreased enzyme removal rate--resulting from a hypofunctional RES--also contributes to the elevated plasma enzyme levels during hemorrhagic hypotension.