Effects of dietary fats and butylated hydroxytoluene on mutagen activation in rats.

The effects of hydrogenated fats and butylated hydroxytoluene (BHT) in the diets of rats on the hepatic activation of benzo(a)pyrene, 2-acetylaminofluorene (AAF), and 2-aminofluorene by liver homogenates (S-9 fraction) were evaluated. The Salmonella/microsomal mutagenicity assay (Strain TA 98) was utilized to determine the mutagenic potential of the activated compounds. The S-9 fraction was obtained from animals fed a 15% fat diet consisting of hydrogenated fats (43% trans-fatty acids) or unsaturated fats (0% trans-fatty acids). BHT was administered orally (0.5%) 6 days prior to sacrifice in both groups. The incorporation of BHT in the diet of rats enhanced the mutagenic potential of AAF and 2-aminofluorene but not of benzo(a)pyrene. This effect was independent of the lipid composition of the diet. The most significant increment in the production of mutagenic metabolites was observed with AAF when BHT and hydrogenated fats were included in the diet of rats. Dietary hydrogenated fats appeared to potentiate the effects of BHT on AAF mutagenicity. Further studies to elucidate the mechanisms by which BHT and hydrogenated fats enhance AAF mutagenicity are warranted.