DNA adduct formation of the carcinogen 2-amino-3-methylimidazo[4,5-f]-quinoline in target tissues of the F-344 rat.

2-Amino-3-methylimidazo[4,5-f]quinoline (IQ), a potent bacterial mutagen present in broiled sardines, cooked beef and beef extract, is a carcinogen in the F-344 rat, affecting mainly the liver and small and large intestines. Using 32P-postlabeling assays, the formation of IQ-DNA adducts was examined in male F-344 rats. Twenty-four hours after i.p. doses (5-50 mg IQ/kg) the liver, small and large intestine each showed the presence of 5 adducts, the liver and large intestine having an average of 18.1 and 2.4 times as many adducts, respectively, as the small intestine. None of these adducts could be detected in vehicle-treated animals. It is concluded that IQ forms specific DNA adducts in target tissues of the F-344 rat.