Prelytic damage of red cells in filtrates from peroxidizing microsomes.

When liver microsomes are incubated in the presence of reduced nicotinamide adenine dinucleotide phosphate (NADPH), their constituent lipids undergo peroxidative degeneration. If erythrocytes are present in such a peroxidizing system, they hemolyze. Filtrates obtained by ultrafiltration of peroxidizing microsomal systems were found to have the capacity to produce prelytic damage in red cells. Filtrates obtained from microsomes that had not undergone peroxidative lipid decomposition were inert. The toxic activity in the active filtrates was not due to continuing oxidation of NADPH nor to continuing liver microsomal lipid peroxidation. Neither the chemical identity of the toxic product or products in active filtrates nor the mechanisms involved in the erythrocyte damage are known at this time.