Comutagenicity and inhibition of DNA repair by metal ions in mammalian cells.

Mutagenic and/or carcinogenic metal compounds may act directly by interaction with DNA and/or indirectly by interference with genetic control and repair mechanisms. In a previous report, we investigated the mutagenicity and comutagenicity of nickel(II) in the V79 Chinese hamster HGPRT-assay. Our present findings demonstrate that like nickel(II), chromium(VI) and cadmium(II) are also comutagenic with UV. Furthermore, there is only a weak concordance with comutagenic effects observed in bacterial test systems. In the case of nickel(II), there is a good correlation between comutagenicity and inhibition of DNA repair, as determined by using the nucleoid sedimentation technique with HeLa cells. This inhibition may occur via replacement of other divalent ions essential in repair enzymes.