In relation to the mechanism by which hemolysis was induced in radiated human erythrocytes in vitro, several inducements of membrane lipid peroxidation and protective effects of V. E and SOD were investigated. Results obtained were as follows:
(1) K⁺-release from erythrocytes was accelerated by radiation prior to hemolysis. These accelerated hemolysis and K⁺-release were protected remarkably by V. E and evidently by SOD.
(2) Mitochondrial Fe²⁺ induced and Fe³⁺-O₂ generating system - ADP induced lipid peroxidation, and microsomal O₂ generating system - induced lipid peroxidation were also protected by V. E and SOD.
(3) Radiation of X-ray or ⁶⁰Co γ-ray accelerated lipid peroxidation of liver homogenate, microsome and liposome. Some of these accelerated lipid peroxidations were protected effectively by V. E and SOD.
These results suggest that O₂ and/or OH·generation by radiation induces of membrane lipid peroxidation, which leads deterioration of membrane resulting in the change of ion permeability and then hemolysis.