Effects of dietary fat and dose level of 7,12-dimethylbenz(alpha)-anthracene on mammary tumor incidence in rats.

Abstract

Summary Female Sprague-Dawley rats maintained on a semisynthetic diet containing 20% corn oil developed more mammary tumors after treatment with a single p.o. dose of 7,12-dimethylbenz(α)anthracene than rats treated similarly but fed a low-fat semisynthetic diet. The tumor yield varied with the dose of 7,12-dimethylbenz(α)anthracene, but the rats on high-fat diet developed more tumors at each of 3 dose levels tested. The type of diet fed after administration of 7,12-dimethylbenz(α)anthracene had a greater influence on mammary tumor incidence than did the type fed before the carcinogen was given, indicating that the effect is exerted mainly at the promotional stage of mammary carcinogenesis.