Studies on rat liver mitochondria. II. Formation of lipid peroxides in mitochondria preserved at 0-4 degrees C.

Levels of lipid peroxides were monitored in freshly isolated rat liver mitochondria, aged mitochondria, and preserved mitochondria by reaction with TBA (2-thiobarbituric acid) and spectrophotometric absorption at 233 nm. In aged mitochondria, the levels of lipid peroxides increased gradually during 120 hr, while in preserved mitochondria they increased rapidly up to 24-48 hr. Under such conditions, the respiratory control coefficients and the levels of total Pi were about 40% those of fresh mitochondria, and the decrease of the levels of lipid peroxides followed the decrease of the respiratory control coefficients and levels of total Pi. These results suggest that stimulation of the formation of lipid peroxides occurs when the vital activity of mitochondria is preserved.