Effects of dietary fat on hepatic microsomal and cytosolic mutagenic activation of 2-aminofluorene.

The present study was designed to examine the effects of different high fat diets on the liver microsomal and cytosolic mutagenic activation of 2-aminofluorene. Male Sprague-Dawley rats were fed either a low fat (5% corn oil) or high fat (20%) diets containing either corn oil (CO), menhaden oil (MO) or beef tallow (BT). After 2 weeks on the test diets, animals from each group were placed on a protocol of weekly injection with 1,2-dimethylhydrazine dihydrochloride (DMH) for 10 weeks. Animals were given DMH injections i.p. and killed 3 h after injection following 5 and 10 DMH treatments. The metabolic activity of liver microsomes and cytosol was assessed by the Ames test using 2-aminofluorene as a standard mutagen. Beef tallow-fed rats had the highest microsomal mutagenic activation, followed by the basal diet. Decreased liver microsomal and cytosolic metabolism of the reference mutagen was detected in the MO and CO diets compared to basal or BT diets. However, there was an increased activity in MO and CO fed groups after week 10, while beef tallow showed a slightly decreased activation. These data indicate that type of dietary fat affects liver microsomal mutagenic activation of carcinogens.