Kinetic aspects of enzyme activity changes in blood plasma during canine hemorrhagic shock

The kinetics of the increase in activities of eight enzymes in plasma was investigated in hemorrhagic shock in dogs (8.0 kPa, 120 min). The time-course of enzyme activity changes in shock differed between animals and depended on their sensitivity to shock. In the shock-sensitive group of dogs an exponential activity increase was already observed in the hypotension period. However, the dogs of the less shock-sensitive group showed a delay of enzyme release with significantly less pronounced elevation of all enzyme activities except creatine kinase. The initial exponential rise of enzyme activities, which approximately followed first-order kinetics, was quantitatively characterized by the release rates. There was a close correlation between the molecular weights of enzymes and their release rates during shock in both groups of dogs. The relevance of the results to mechanisms of enzyme transport from the cell into the blood is discussed.