Impaired Clearance of Enzymes in Mice Infected With the Lactic Dehydrogenase Agent

Mice infected with the lactic dehydrogenase (LDH) agent cleared intravenously administered lactic dehydrogenase and isocitric dehydrogenase from the peripheral circulation at a slower rate than normal mice. No difference was found between normal and infected animals in the rate of clearance of alkaline phosphatase. Carbon tetrachloride, which liberates endogenous enzymes into the circulation by damaging cells, resulted in a more prolonged elevation of lactic dehydrogenase, isocitric dehydrogenase, and malic dehydrogenase in the plasma of infected animals than in normal animals. The onset of impaired enzyme clearance occurred within 13 hours after injection of the LDH agent and persisted for months. The clearance of colloidal carbon particles was also impaired early in the course of infection but returned to normal within 1 week. Evidence is discussed which suggests that impaired clearance of normally released endogenous enzymes might be responsible for the increase in plasma enzyme activity following infection with the LDH agent.