Mutagen screening by a simplified bacterial fluctuation test: use of microsomal preparations and whole liver cells for metabolic activation.

We describe the use of a simplified bacterial fluctuation test to detect induced mutation, either incorporating liver microsomal or whole liver cell preparations. We have evaluated both types of test using three agents. The fluctuation assay seems somewhat slower, simpler and more sensitive than a conventional plating test with microsomes. A whole cell preparation appears marginally more effective than a microsomal fraction for metabolic activation of 9,10-dimethyl-1,2-benzanthracene, but rather less effective for benz(a)pyrene and 2-acetamidofluorene. Ultimately the usefulness of activation by whole cells may depend upon whether the method can give a correlation with carcinogenicity that is more quantitative than microsome methods and better reflects organ and species specificity.