The role of mitochondrial glutathione in the defence against Fe2+/ascorbate induced peroxidation of rat liver mitochondria.
The protective role of the glutathione system against oxidative stress was studied in the model of Fe2+/ascorbate induced peroxidation in isolated rat liver mitochondria. There was a successive diminution of the mitochondrial glutathione pool, essentially due to losses of the reduced form (GSH) during the initiation phase of peroxidation, while the redox state of glutathione was not influenced significantly before the onset of massive malondialdehyde formation. Oxidizable substrates such as glutamate/malate and 3-hydroxybutyrate affected peroxidation by extending the period of the induction phase. Obviously that was due to the supply of NADPH to recover GSH via GSSG-reductase as evidenced by the parallel decline of the NADP(H) and the glutathione-system redox states. Although the data strongly support the fact that mitochondrial glutathione plays a central role in the defence against oxidative stress, there are, under special conditions of a high succinate supply, other potent defence systems in isolated mitochondria.