Pre-screening of carcinogens by studying of DNA synthesis inhibition and gene mutations in mammalian cells.

The ability to induce gene mutations at the HGPRT locus in Chinese hamster V79 cells and to inhibit DNA synthesis in human EUE cells has been followed in eighteen chemical substances and ultraviolet light. The aim was to determine whether following of inhibition of DNA synthesis in impaired human cells may serve as an indicator of the mutagenicity of the relevant chemical substance. The results permit us to assume that following of DNA synthesis, the so-called DNA-inhibition test provides a preliminary information on the genotoxicity of the chemical substance, although the degree of inhibition of DNA synthesis need not necessarily denote the measure of the mutagenic effect of the substance. As certain further tests, utilising in vitro mammalian cells, so also the DNA-inhibition test yields a certain percentage of false positive results. Hence, it is important to combine this test with further express in vitro tests on the level of mammalian cells.