The effects of various inducers on the activities of drug-metabolizing enzymes including aflatoxin B
1 activation were studied in Syrian golden hamsters. Activity for aflatoxin B
1 was determined by aflatoxin B
1-DNA adducts formation. The treatments of hamsters with 3-methylcholanthrene, α-naphthoflavone and benzo(a)pyrene elevated markedly the activity for aflatoxin B
1 by 2460, 1380 and 450%, respectively. Phenobarbital induced slightly and isosafrole and ethanol did not induce the activity for aflatoxin B
1. Pregnenolone-16α-carbonitrile decreased aflatoxin B
1 activation to 51% of that of the non-treated animals. These results were in good accordance with the induction rate of a form of cytochrome P-450(P-450
AFB) which has potent activity to aflatoxin B
1. Characteristics in the induction of mixed function oxidases of hamsters by these inducers, especially in respect to benzo(a)pyrene metabolizing enzyme, seemed to differ from those of rats. These results suggest that the activity for aflatoxin B
1 in hamster is inducible by 3-methylcholanthrene-type inducers and that hamster is a suitable animals model to study the mechanism of aflatoxin B
1-hepatocarcinogenesis.
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