Metabolism of 7,12-dimethylbenz(a)anthracene by alveolar macrophages containing ingested ferric oxide, aluminum oxide...

Rat alveolar macrophages with ingested aluminum oxide (Al2O3), ferric oxide (Fe2O3) or carbon particles were incubated for 24 hours with 3H-7, 12-dimethylbenz(a)anthracene (DMBA). Essentially the same amounts and types of metabolites were produced by and released from macrophages with ingested Fe2O3 and Al2O3 particles. Smaller quantities of DMBA and its metabolites could be extracted with ethyl acetate from the culture media and cell lysates of macrophages with ingested carbon particles than from those with Fe2O3 and Al2O3 particles. Also, more of the intracellular radioactivity was associated with insoluble material in macrophages with ingested carbon than in those with the other two types of particles. The results suggest that the inability of Al2O3 to act as a co-carcinogenic carrier for polycyclic aromatic hydrocarbons (PAH) is not related to its effect on PAH metabolism. However, adsorption of PAH and their nonpolar metabolites to carbon may alter the exposure pattern of pulmonary tissues to PAH and their metabolites.