Apparent activation of 2-acetylaminofluorene and some aromatic amines by cytosolic preparations

The results presented here confirm that 2-acetylaminofluorene (AAF) can be activated to a mutagen by S105 rat liver post-microsomal fraction. The activity is Aroclor-inducible. It appears partly NADPH-independent, but on repeated centrifugation the NADPH independence is lost though the NADPH-dependent activation is retained. S105 activation is obtained whether the fraction is prepared with 0.15 M KCl or 0.25 M sucrose. Increasing amounts of S105 give increasing activation, with no evidence of an optimum. Activation by S105 is reduced in the presence of excess S9 and is inhibited by norharman. Under the same conditions, S105 produces mutagenic metabolites of 2-aminofluorene and 2-aminoanthracene but not ethidium bromide, dimethylaminoazobenzene or benzo(alpha)pyrene.