Selenium effects on the carcinogenicity and metabolism of 2-acetylaminofluorene

Addition of 4 ppm Se to the drinking water of male albino rats fed diets containing 0.03% 2-acetylaminofluorene (AAF) provided protection against hepatic damage and also resulted in at least 50% reduction in liver tumor incidence. An in vitro assay system utilizing microsomes from Se supplemented or non-supplemented 3-methylcholanthrene (MC) induced rats was used to determine the effect of oral Se intake on the metabolism of AAF. Oral Se administration led to an increase in ring hydroxylation and a decrease in N-hydroxylation. Addition of Se to the microsomal assay system increased 3-OH AAF formation and decreased N-OH AAF formation, thus shifting the balance of metabolism toward detoxification pathways.