The effect of ferric iron complex on isolated rat liver mitochondria. II. Ion movements.

It has been found that addition of iron(III)-gluconate complex to rat liver mitochondria disturbed the mitochondrial Ca2+ transport. Indirect evidence when the changes in the membrane potential during the transport of Ca2+ were followed, as well as direct evidence, when the fluxes of Ca2+ were monitored by a Ca2+-selective electrode, indicated that this iron complex induced an efflux of Ca2+ from liver mitochondria. The mechanisms by which iron induced Ca2+ release appeared to be linked to the induction of lipoperoxidation of mitochondrial membrane. The mitochondrial membrane, however, did not become irreversibly damaged under these conditions, as indicated by its complete repolarization. It was also shown that the induction by iron of lipoperoxidation brought about an efflux of K+ from mitochondria.