Change of the lipid hydroperoxide level in mouse organs on ageing.

Change in the total level of tissue lipid hydroperoxides during ageing in the mouse was determined by our newly developed specific and sensitive method. The hepatic level of lipid hydroperoxides of 5-week-old mice was 239 +/- 31 pmol/mg protein. Hydroperoxide levels in the liver of 20-, 30-, 40-, 60- and 85-week-old groups were 487 +/- 115, 348 +/- 87, 395 +/- 65, 498 +/- 98 and 431 +/- 81 pmol/mg protein, respectively, and these values were significantly higher than the content of the 5-week-old animals. In the heart and kidney, the level of lipid hydroperoxides increased also significantly at 20 weeks of age compared with that of the 5 week-old mouse. The hydroperoxide level did not increase significantly thereafter until 85 weeks of age. The hydroperoxide level in the brain did not change during 5-85 weeks of age.