Synergistic toxicity of carbon tetrachloride and several aromatic organohalide compounds.

Subacute (20 days) oral administration of hexachlorobenzene (HCB) or the organohalide mixtures polybrominated biphenyls (PBB) or polychlorinated biphenyls (PCB) greatly increased th susceptibility of male rats to the toxic effects of carbon tetrachloride (CCl4). CCl4-induced acute growth retardation, renal tubular functional impairment and hepatocellular necrosis were quantitatively greater in rats pretreated with the aromatic organohalides than in naive rats. Pretreatment with HCB, PBB or PCB also reduced survival after i.p. administration of CCl4 and increased the severity of morphological liver injury. Despite functional impairment, only minor histological alterations attributable to CCl4 were detected in the kidney. CCl4 as well as HCB, PBB or PCB increased the lipid content of the liver, but not the kidney. CCl4 administration depressed energy-dependent accumulation of organic ions by renal cortical slices in vitro in a dose-dependent manner and increased the basal rate of respiration of renal cortical tissue in vitro. It is concluded from these results that exposure to certain commercial aromatic organohalides can greatly alter organ response to toxicants such as CCl4.