EFFECT OF ASBESTOS-ASSOCIATED METAL-IONS ON BINDING OF BENZO(A)PYRENE TO MACROMOLECULES INVITRO

In seeking an explanation for the high risk of malignancy in workers exposed to both asbestos and benzo (a) pyrene inhaled in cigarette smoke, experiments have been carried out to test the effect of asbestos-associated trace metals on the covalent binding of benzo(a)pyrene in vitro. Most of the metals tested-nickel, cadmium, chromium, zinc, manganese, and copper-caused an overall decrease in the binding of benzo(a)pyrene in microsomal incubations containing exogenous DNA. That this represented a reduction in the binding to DNA was confirmed in the cases of zinc, nickel, and chromium. Magnesium caused a very slight increase in binding, and ferrous and ferric ions, while reducing the binding to DNA, caused an increase in binding to some component of high molecular weight in the incubation mixtures, over a narrow concentration range. The significance of these findings is discussed in relation to the development of malignant disease associated with asbestos exposure. © 1978.