Biochemical evidence for chemical and/or topographic differences in the lipoperoxidative processes induced by CCl₄ and iron

Isolated rat hepatocytes, treated with CCl₄ or ADP-Fe³⁺ complex show an enhanced lipid peroxidation and a decreased glucose 6-phosphatase activity. Lipid peroxidation is much more stimulated by ADP-Fe³⁺ or Fe³⁺ than by CCl₄, when the metal and the haloalkane are used at a similar concentration. Increasing rates of lipid peroxidation in the different experimental conditions do not correlate with the degree of glucose 6-phosphatase inactivation, which is produced by CCl₄ and not by a similar amount of ferric iron. In the case of iron, its intracellular concentration must be higher to give the enzyme inactivation exerted by CCl₄. Higher intracellular levels of iron are reached when the metal is added to the cell suspension together with ADP. Under these conditions there is inactivation of glucose 6-phosphatase. Possible mechanisms accounting for a different enzyme sensitivity to iron and CCl₄ are discussed.