Mutagenicity of benzidine and 4-aminobiphenyl after metabolic activation with isolated hepatocytes and liver 9000 X g supernatant from rat, hamster and guinea pig.

The mutagenicity of benzidine and 4-aminobiphenyl towards Salmonella typhimurium strain TA1538 was measured in the presence of isolated hepatocytes from rat, hamster and guinea pig. The mutagenic potency of these compounds was also assayed with S9 (9000 X g supernatant) prepared from disrupted hepatocytes. The influence of acetyl coenzyme A, the cofactor for the acetylation reaction, on the mutagenicity of these aryl amines was investigated. For all 3 animal species it was found that the mutagenicity of benzidine is higher with intact hepatocytes than with S9 prepared from disrupted hepatocytes. Addition of acetyl coenzyme A to the S9 fraction increased the mutagenicity of benzidine. In contrast to benzidine, the mutagenicity of 4-aminobiphenyl appeared to be lower with hepatocytes than with S9. Addition of acetyl coenzyme A to the S9 fraction decreased the mutagenicity of 4-aminobiphenyl. The mutagenic potency of 4-aminobiphenyl was almost equal in the presence of the liver preparations from the 3 different species, whereas obvious species differences were seen with benzidine.