Binding of hexachloroethane to biological macromolecules from rat and mouse organs

Hexachloroethane (HCE) binds to macromolecules of rat and mouse both in vivo and in vitro after metabolic activation. The covalent binding index (CBI) to liver DNA in vivo is comparable to that of compounds classified as weak-moderate initiators and is of approximately the same order of magnitude as those of other halocompounds such as 1,2-dichloroethane. HCE is bioactivated in vitro by microsomal enzymatic systems from murine liver and kidney and, to a greater extent, by cytosolic fractions from all assayed organs. HCE is less reactive than 1,1,2,2-tetrachloroethane, which is more toxic and oncogenic. The ability of hexachloroethane and five other chloroethanes to react covalently with mouse liver DNA both in vivo and in vitro parallels the relative oncogenic potency of these hepatocarcinogenic chemicals in mouse liver.