INFLUENCE OF IRON ON THE INDUCTION OF HEPATIC-TUMORS AND PORPHYRIA BYOCTACHLOROSTYRENE IN C57BL 1OSCSN MICE/

Octachlorostyrene (OCS) is an environmental contaminant, present in fi sh of Northern European waters and the Great Lakes of America. It has many distribution and toxic similarities to hexachlorobenzene (HCB). A dministration of OCS at 0.01% of the diet to C57BL/10ScSn mice within iron overload for 18 months gave only a low incidence of hepatic nodul ar hyperplasia (2/10 survivors) and no hepatocellular adenomas or carc inomas. In contrast, with a similar regime, HCB causes severe liver ca ncer or nodules in all exposed mice. Whole body autoradiography of mic e given [C-14]OCS or [C-14]HCB showed no gross variations in distribut ion or covalent binding of the radiolabelled compound to account for t he difference between the chemicals in the development of tumours. In 12-week studies, the CYP1A subfamily was induced to a greater degree b y HCB than OCS and iron-enchanced uroporphyria was significantly great er with HCB. The findings are consistent with the proposal that uropor phyria and liver cancer induced in mice by HCB are associated through related mechanisms, but occur to a significantly lesser extent with OC S.