Identification of 4-hydroxynonenal as a cytotoxic product originating from the peroxidation of liver microsomal lipids.

During the NADPH-Fe induced peroxidation of liver microsomal lipids, products are formed which show various cytopathological effects including inhibition of microsomal glucose-6-phosphatase. The major cytotoxic substance has been isolated and identified as 4-hydroxy-2,3-trans-nonenal. The structure was ascertained by means of ultraviolet, infrared and mass spectrometry and high-pressure liquid chromatographic analysis. Moreover, 4-hydroxynonenal, prepared by chemical synthesis, was found to reproduce the biological effects brought about by the biogenic aldehyde. Preliminary investigations suggest that as compared to 4-hydroxynonenal very low amounts of other 4-hydroxyalkenals, namely 4-hydroxyoctenal, 4-hydroxydecenal and 4-hydroxyundecenal are also formed by actively peroxidizing liver microsomes. In the absence of NADPH-Fe liver microsomes produced only minute amounts of 4-hydroxyalkenals. The biochemical and biological effects of synthetic 4-hydroxyalkenals have been studied in great detail in the past. The results of these investigations together with the finding that 4-hydroxyalkenals, in particular 4-hydroxynonenal, are formed during NADPH-Fe stimulated peroxidation of liver microsomal lipids, may help to elucidate the mechanism by which lipid peroxidation causes deleterious effects on cells and cell constituents.