In vitro assays for recombinogenic activity of chemical carcinogens and related compounds with Saccharomyces cerevisiae D3.

A total of 101 carcinogens, noncarcinogens, metals, and promoters representing a wide variety of chemical classes was tested to determine whether they increased mitotic recombination in Saccharomyces cerevisiae D3. A metabolic activation system prepared from homogenates of livers from rats that had been pretreated with Aroclor 1254 (a mixture of polychlorinated biphenyls) was incorporated in the assay procedure. All of the ultimate carcinogens (20/20) and 38% of the procarcinogens (18/48) increased mitotic recombination. Of the noncarcinogens 29% (6/21) also increased mitotic recombination. A improved metabolic activation procedure appears to be required to increase the probability of detecting procarcinogens by this method. The carcinogens thioacetamide, natulan, auramine, safrole, and 1'-hydroxysafrole increased mitotic recombination in S. cerevisiae D3 (the last compound was marginally positive), but they were negative in assays with Salmonella typhyimurium.