[Effect of o-benzoquinone derivatives on free radical processes, induced in rat liver microsomes by carbon tetrachloride].

The effect of o-benzoquinones on free radical reactions stimulated in rat liver microsomes was studied by using 14C-labeled CCl4. It was found that o-benzoquinones decrease the amount of 14C from CCl4 covalently bound to proteins and lipids. This effect may be due to both decontamination of free radical products of CCl4 metabolism and to inhibition of their synthesis by a shunt via the NADPH-dependent electron transport chain of microsomes. There is evidence that under conditions of ClC4 poisoning the protective effect of o-benzoquinones correlates with their ability to inhibit the covalent binding. It is concluded that covalent binding plays the key role in CCl4 hepatotoxicity.