Cytotoxicity and mutagenicity of dinitrotoluenes in Chinese hamster ovary cells.

Technical grade dinitrotoluene (DNT), a mixture composed predominantly of 2,4- and 2,6-DNT but containing lesser amounts of 2,3-, 2,5-, 3,4- and 3,5-DNT, has been shown to be a hepatocarcinogen in rats, The mutagenicity of these compounds has been evaluated using the CHO/HGPRT system, a quantitative mammalian somatic cell mutational assay. Dinitrotoluenes were tested for their ability to induce mutation to 6-thioguanine (TG) resistance in the presence and absence of microsomal preparations (PMS) from rats pretreated with the mixed function oxidase inducer Aroclor 1254. A marked difference in cytotoxicity of the isomers was observed. However, neither technical grade DNT nor any of the purified isomers resulted in a significant increase in the TG-resistant fraction of surviving cells, with or without added PMS.