Species differences in the covalent binding of p-chloro-o-toluidine to DNA

The covalent binding of p-chloro-o-toluidine to hepatic macromolecules was assessed in rats and mice. At all timepoints investigated covalent binding to DNA was most marked in mice, whilst binding to proteins was more pronounced in rats. Two major hydrophobic DNA-adducts were formed in both species. One of these was formed to a much greater extent (6-30 fold) in mice. Thus, species differences in the metabolism of p-chloro-o-toluidine could account for the fact that mice are more susceptible to the carcinogenic effects of this compound.