[Membrane disorder and free radical].

The aim of this study is to confirm cholesterol-derived hydroperoxides in membrane lipids as indices of free radical or active oxygen-induced membrane disorder or pathological changes at legal medicine. First, 7 alpha- and 7 beta-hydroperoxycholesterol (7 alpha-OOH and 7 beta-OOH) were synthesized. Then, these were identified in lipids from human fatty liver by liquid chromatography-mass spectrometry. Secondly, the method for quantifying 7 alpha-OOH and 7 beta-OOH by high-performance liquid chromatography with chemiluminescent detection (HPLC-CL) was developed. Finally, the following membrane disorders were examined based on lipid peroxidation. Elevated lipid peroxidations were found in erythrocyte membranes of alcoholic patients, in alcoholic fatty liver, and in muscle of alcohol dosed rats. Enhanced lipid peroxidation was induced in rat kidney by paraquat. In addition, lipid peroxidation was increased in brains of senile dementia as well as in atheroscleroic plaque. Thus, we confirm 7-hydroperoxycholesterol as a marker of free radical-induced oxidative stress.