The fate and acute toxicity of aflatoxin B-1 in the mastomys and rat

摘要

The fate and acute toxicity of aflatoxin B-1 (AFB(1)) were studied in the mastomys (Praomys coucha) and compared with Fischer rats. The experiment regarding the fate of [H-3]AFB(1) showed that the radioactivity was excreted mainly through the feces, more rapidly in the mastomys than in the rat, regardless of whether [H-3]AFB(1) was given orally or intravenously. The levels of radioactivity bound to the liver DNA were lower in the mastomys than in the rat, indicating that the levels of AFB(1) binding to the macromolecules in the liver were lower in the mastomys. Consistent with such differences in the fate of AFB(1) between the two species, the mastomys were far more resistent to the acute effects of AFB(1) than were the rats. Oral administration of AFB(1) at a dose of 1.0 mg/kg to rats caused marked microscopic changes in the liver, involving hepatic necrosis and proliferation of bile ducts, but at a dose of 4.0 mg/kg to mastomys caused no pathological changes in the liver or kidneys, and at a dose of 10.0 mg/kg caused only glycogen deposition in hepatic cells in a limited area. The observed differences in susceptibility to the toxic effects of AFB(1) and in the fate of AFB(1) between the two species are in accord with our previous finding that liver cytosol in the mastomys inhibits microsome-mediated AFB(1)-DNA binding in vitro more strongly than in rat liver. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 21]