Formation and Destruction of Thermo-Lipofuscin in Mitochondria

Previously, we have demonstrated that moderate heating of mitochondria isolated from rat liver induces the formation of lipofuscin -a pigment of ageing. The resulting thermo-lipofuscin has a characteristic fluorescence intensity in the blue region (460 nm) upon excitation at the near UV (360 nm) like normal lipofuscin found in cells. In this paper, we studied the effect of various substances on the processes of formation and destruction of mitochondrial thermo-lipofuscin. Contrary to our expectations, anti-oxidants such as ionol, histidine and imidazole have accelerated the process of formation of thermo-lipofuscin in mitochondrial suspension. Thermo-lipofuscin has formed more slowly in a buffer of pH 6. Formation of thermo-lipofuscin has been reduced upon activation of mitochondrial respiration by succinate. The formed thermo-lipofuscin has been cleaved to some degree by reducing agents with an active sulfhydryl group -glutathione, cysteine, dithiothreitol. It can be assumed that one of the ways of formation of thermo-lipofuscin is oxidation of protein's SH-groups.