Effect of endurance exercise training on hepatotoxicity induced by aflatoxin B
1 (AFB
1) was studied in rats. Rats were subjected to swimming with 1%BW resistance for 30min, 5 days/week for 14 weeks before administration of AFB
1. Endurance exercise training induced high physical fitness as shown by reduction in resting heart rate and increase in the activities of mitochondrial succinate dehydrogenase and citrate synthase in the gastrocnemius muscle. Water-immersed rats had similar basal physical fitness when compared with that of the untrained rats. Endurance exercise training as per the above schedule followed by a single i.p. injection of AFB
1 (2mg/kg BW) caused a significant increase in the activities of serum alanine aminotransferase (ALT) by 6.6 fold and aspartate aminotransferase (AST) by 1.8 fold and increased the severity of histopathologic hepatic necrosis at 24h after AFB
1 administration. Endurance exercise training potentiated AFB
1-induced hepatotoxicity by increasing the activity of the hepatic monooxygenase enzymes aniline hydroxylase and
p-nitroanisole-O-demethylase. These results suggest that potentiation of AFB
1-hepatotoxicity by endurance exercise training may be due to an increase in the metabolic formation of AFB
1-8, 9-oxide, which, in turn, causes a marked increase in AFB
1 binding to hepatic DNA and proteins.
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