Lead and mercury mutagenesis: Role of H2O2, superoxide dismutase, and xanthine oxidase

✍ Scribed by Maria E. Ariza; Gautam N. Bijur; Marshall V. Williams

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 382 KB
• Volume: 31
• Category: Article
• ISSN: 0893-6692
• DOI: 10.1002/(sici)1098-2280(1998)31:4<352::aid-em8>3.0.co;2-k

✦ Synopsis

It has been suggested that reactive oxygen interme-0.8 and 1 mM, respectively. Pb 2/ and Hg 2/ (0.1diates (ROIs) may have a role in the genotoxic ef-1 mM) had no effect on the activities of partially fects of lead (Pb 2/ ) and mercury (Hg 2/ ), but there purified catalase, glutathione peroxidase, or glutahave not been any definitive studies demonstrating thione reductase, important enzymes involved with a causal relationship between the induction of ROIs antioxidant defense, but these metals stimulated the by these metals and mutagenesis. We previously activities of copper-zinc superoxide dismutase demonstrated, using the transgenic Chinese ham-(CuZn-SOD) and xanthine oxidase (XO). Allopurister ovary cell line AS52, that low concentrations nol (50 mM), a specific inhibitor of xanthine oxi-(0.1 -1 mM) of Pb 2/ and Hg 2/ are mutagenic. In dase, inhibited the induction of H 2 O 2 by Pb 2/ (0.8the present study, using a novel histochemical com-1 mM) and Hg 2/ (1 mM) and also inhibited Pb 2/puter-enhanced image analysis technique, we dem-and Hg 2/ -induced mutagenesis. These results demonstrate that Pb 2/ and Hg 2/ induce the formation onstrate that Pb 2/ and Hg 2/ disrupt the redox status of H 2 O 2 in AS52 cells by at least two distinct mecha-of AS52 cells by enhancing the activities of CuZnnisms. One is characterized by the rapid induction SOD and XO. Furthermore, the results of these studof H 2 O 2 following treatment of cells with concentra-ies also demonstrate that there is a causal relationtions of Pb 2/ or Hg 2/ below 0.8 and 1 mM, respec-ship between the induction of H 2 O 2 by these metals tively, while the second occurs in AS52 cells treated and mutagenesis. Environ. Mol. Mutagen. 31: with concentrations of Pb 2/ or Hg 2/ greater than 352-361, 1998.