Red cell lysis coupled to the peroxidation of liver microsomal lipids. Compartmentalization of the hemolytic system

As a contribution to the understanding of the mechanisms by which addition of erythrocytes to liver microsomes incubated in the NADPH dependent system results in hemolysis, experiments are presented here in which the system containing actively peroxidizing microsomes was separated from the system containing the red blood cells by a dialysis membrane. It is shown that when liver microsomes were incubated with NADPH, lipid peroxidation, as measured by the formation of malonic dialdehyde (MDA), rapidly took place. The MDA concentration tended to equilibrate across the dialysis membrane. After a lag phase of 60 min, lysis of erythrocytes contained in the dialysis tube, started. It reached its maximal level (more than 80%) at 110 min of incubation. These results strongly suggest the possibility that toxic products originating during the course of lipid peroxidation induce pathological effect at distant loci. Furthermore, the accomplishment of a compartmentalization of the two systems involved in the reaction, may offer an approach to the recognition of the toxic factors.