Toxic effects of methylated benz[a]anthracenes in liver cells.

Monomethylated benz[ a]anthracenes (MeBaAs) are an important group of methylated derivatives of polycyclic aromatic hydrocarbons (PAHs). Although the methyl substitution reportedly affects their mutagenicity and tumor-initiating activity, little is known about the impact of methylation on the effects associated with activation of the aryl hydrocarbon receptor (AhR)-dependent gene expression and/or toxic events associated with tumor promotion. In the present study, we studied the effects of a series of MeBaAs on the above-mentioned end points in rat liver cell lines and compared them with the effects of benz[ a]anthracene (BaA) and the potent carcinogen 7,12-dimethylbenz[ a]anthracene (DMBA).