LINEAR DOSE-RESPONSE CURVE FOR THE HEPATIC MACROMOLECULAR BINDING OF AFLATOXIN-B1 IN RATS AT VERY LOW EXPOSURES

  • 1 January 1982
    • journal article
    • research article
    • Vol. 42  (9) , 3659-3662
Abstract
The possibility of a low dose threshold for rat liver macromolecular binding of aflatoxin B1 was investigated. Doses in ng/kg of radiolabeled aflatoxin B1 produced measurable covalent binding of aflatoxin to DNA, RNA and protein, and the extent of this binding increased linearly over a dose range of 10-1000 ng/kg. Macromolecular adduct formation was observed at the lowest dose used (10 ng/kg) which is within the human exposure range. Although diethyl maleate caused a reduction in hepatic glutathione from 5 to 2.3 .mu.mol/g of liver and a slight increase in macromolecular adduct levels, the dose-response curve for macromolecular adduct formation remained linear in both diethyl maleate-pretreated and control groups. Macromolecular binding of aflatoxin B1 is essentially a linear function of dose at low exposures. Hepatic glutathione offers little if any protection against this binding. [Aflatoxin B1 is a carcinogen.].