Activity of the DNA repair enzyme uracil-DNA-glycosylase in mammalian species differing in longevity and the level of liver cell ploidy

The activity of uracil-DNA glycosylase (UDG) was studied for livers of 13 mammalian species belonging to four orders. DNA contents were also measured in isolated hepatocytes. The enzymatic activity was shown to increase with the increase in the mean ploidy of liver parenchymal cells. The activity of UDG was 20 times as high when the mean liver cell ploidy of different mammalian species doubled. A reverse dependence between the UDG activity and species life spans is also revealed.