The food pyrolysis product IQ enhances its own activation

The metabolic activation of the food pyrolysis product 2-amino-3-methylimidazo (4,5-f) quinoline (IQ) to mutagenic intermediates in the Ames test was studied using hepatic activation systems from control and IQ-treated rats. Hepatic S9 preparations from IQ-treated rats were more efficient than control in converting IQ to mutagens. An increase was also seen when isolated microsomes were employed as activation systems but this was less pronounced. The microsome-mediated mutagenicity of IQ was potentiated by addition of the cytosolic fraction from control and IQ-treated rats, the latter being more effective. It is concluded that IQ, at the doses employed in the present study, enhances its own bioactivation to genotoxic metabolites by stimulating both its microsomal and cytosolic metabolism.