Dose-response relationships for hepatic aflatoxin B1-DNA adduct formation in the rat in vivo and in vitro: The use of immunoslot blotting for adduct quantitation

An immunoslot blotting (ISB) method for quantitating aflatoxin B-1-DNA addu ct levels has been developed and used to examine the relationship between d ose and hepatic aflatoxin B-1-DNA adduct levels in rats fed aflatoxin B-1 ( AFB(1)) in the diet at dose levels of between 0.5 and 10 mu g/kg/day. The m ethod has also been used to examine the dose-response relationship for addu ct formation in precision-cut rat Liver slices incubated with AFB(1) at con centrations between 0.01 and 2 mu M. For the feeding studies, groups of male Fisher F344 rats were given AFB(1) in the diet for periods of 1 to 10 weeks and hepatic DNA adduct levels dete rmined using ISB. The time for adduct levels to reach steady-state conditio ns was determined in animals given approximately 10 mu g of AFB(1)/kg/day a nd steady-state levels at lower concentrations measured. The time course for the accumulation of AFB(1)-DNA adducts in rat liver sli ces incubated with AFB(1) at 0.5 mu M has been investigated and the relatio nship between adduct formation and AFB(1) concentration over a wide concent ration range in liver slices has been determined. Teratogenesis Carcinog. M utagen. 19:157-170, 1999. Published 1999 Wiley-Liss, Inc.