On the mechanism of citrate and isocitrate protective action on rat liver mitochondria.

Both citrate and isocitrate prevent the damage (efflux of endogenous Mg2+ and pyridine nucleotides, decay of delta psi and release of accumulated Ca2+) induced in rat liver mitochondria by Ca2+ and phosphate fluxes. Addition of fluorocitrate suppresses the action of isocitrate, but not that of citrate. The same results have been obtained with mitochondria isolated from animals treated with fluoroacetate. It is suggested that citrate directly and isocitrate by prior conversion into citrate exert the protective action by chelating and retaining Mg2+ within the mitochondria.