DNA binding and mutagenicity of aflatoxin B1 catalyzed by isolated rabbit lung cells

The abilities of different rabbit lung cell types to bioactivate aflatoxin B 1 (AFB 1 ) to a DNA-binding and mutagenic metabolite have been examined. Microsomes were prepared from centrifugal elutriation-enriched preparations of isolated rabbit lung cell types. The activation of [ 3 H]AFB 1 (5.0 or 200 μM), measured indirectly as covalent binding to calf thymus DNA, was concentrated in microsomes from the non-ciliated bronchiolar epithelial (Clara) cell-rich fractions (13 -22 times the activity of whole lung microsomes). Microsomes from type II cell-rich fractions had minimal activity. Significant correlations were detected between the rates of microsomal DNA binding and the percentages of Clara cells in the fractions