Swelling and lysis of rat liver mitochondria induced by ferrous ions.

The possibility that ascorbateand reduced glutathioneinduced swelling and lysis of mitochondria (1,2) were dependent on some metal, such as iron, which was contaminating reagents, or even the nonheme iron in mitochondria led us to investigate the action of added iron. The ferrous ion was of special interest as a result of its role in several reactions catalyzed by ascorbate (3, 4). The promotion of swelling by many ions, including iron, has been reported by several workers (5-7), but the characteristic phenomena to be described here were apparently obscured by various conditions. Unlike swelling induced by many other substances uch as phosphate and thyroxine, (8, 9), swelling with ascorbate, reduced glutathione, or Fe++ is not dependent on endogenous or added substrates. There is a close correlation between lipid peroxide formation and swelling or lysis induced by Fe*, J ‘ust as has been observed with ascorbate and oxidized plus reduced glutathione (1). Whether or not such effects contribute to physiological control or pathological phenomena remains to be seen, but these studies with isolated mitochondria provide additional information about structure and permeability control in the mitochondrial membranes.