Dietary modulation of DNA adduct formation of the food mutagen 2-amino-3-methylimidazo[4,5-f]quinoline in the male Fischer 344 rat.

In numerous in vivo systems it has been shown that diets high in menhaden oil (a fish oil high in omega-3 fatty acids) can inhibit the carcinogenic process. In the present study, we have assessed the effects of a diet containing menhaden oil on 2-amino-3-methylimidazo[4,5-f]quinoline (IQ)-DNA adduct formation in target tissues of the male Fischer 344 rat. Young adult male Fischer 344 rats were maintained on either a) an AIN-76A diet containing 5% corn oil, b) an isocaloric AIN-76A diet modified to contain 2% corn oil and 19% menhaden oil (MO diet), or c) a regular laboratory rodent diet (chow diet) for 6 weeks prior to receiving a single oral dose of 10 or 50 mg IQ/kg. Groups of four animals were killed 1 or 6 days after IQ administration. Using 32P-postlabeling assays, IQ-DNA adducts were isolated and quantitated in the liver, small intestine, and large intestine. Adduct patterns were similar in all cases. Adduct levels, expressed as relative adduct labeling values (RAL x 10(7)), were related to dose in all three tissues, with liver levels up to 10-fold higher than the large intestine and up to 20-fold higher than the small intestine. On day one, liver adduct levels in animals on the AIN-76A diet were similar to those in animals on the chow diet, but those in animals on the MO diet were approximately 2-fold lower.(ABSTRACT TRUNCATED AT 250 WORDS)