The Study of Mechanisms of Aflatoxin Detoxification in Animals

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In order to study the glutathione-S-transferase (GST) activity toward aflatoxin BI (AFBI) epoxide in rodents, we performed in vitro studies of the cytosolic GST activity using mastomys, rat, mouse and hamster liver. AFBI, glutathione and co-enzymes were incubated with the liver cytosol fraction in the presence of the hamster microsomes, which were used to generate AFBI-epoxide as a substrate for GST, and then AFBI-glutathione conjugate formed was analyzed by HPLC. The result demonstrated that GST activity was highest in mastomys liver, and higher in the hamster and mouse livers than in the rat liver, correlating with the difference of the sensitivity of these species to the AFBI toxicity. Sex differences were noted in the rat, the female activity being higher than the male activity. Comparison of cytosolic GST activity among different organs in these species revealed that the CST activity was higher in the liver than in the small intestine, kidney, testis, lung and brain in the mastomys, hamster, maouse and female rat. In the male rat, the small intestine showed the highest activity among the organs. The AFBI aldehyde reductase activity in the liver cytosol was also measured by determining metabolic conversion of AFBI-aldehyde to AFBI-dialcohol and compared among different animal species.