A comparative study on Aflatoxin B1 metabolism in mice and rats

Abstract

In vivo metabolic studies on rats and mice revealed a marked difference in the fluorescent compounds produced after ingestion of aflatoxin B1. The mouse converted aflatoxin B1 to three unknown fluorescent compounds, designated X1, X2 and X3 and the known aflatoxin M1, while the rat was only capable of producing aflatoxin M1. The results suggested that metabolites X1, X2, X3 and aflatoxin M1 were not part of a major metabolic pathway, but produced independently. These unknown yellowish-green fluorescent compounds did not seem to be conjugated with sulphate or glucuronic acid. In vitro incubations of various mouse liver cell fractions with aflatoxin B1 showed that metabolites X1, X2, X3 and aflatoxin M1, could only be produced by the microsomal fraction and that NADPH was needed as a co-factor. The differences in aflatoxin metabolism by mice and rats are discussed in relation to the apparent resistance of the mouse to the carcinogenic effects of this toxin. © 1971, The British Empire Cancer Campaign for Research. All rights reserved.