title: Dl-α-tocopherol enhances the herbicide 1,1'-dimetyl-4,4'-bipyridium dichloride (paraquat, PQ) genotoxicity in cultured anuran leukocytes.
abstract: This cytogenetic and pharmacological study attempts to clarify genotoxicity-enhancement-effect of dl-α-tocopherol (one form of vitamin E) in combination with the herbicide 1,1'-dimetyl-4,4'-bipyridium dichloride (paraquat, PQ) on cultured anuran leukocytes using the superoxide dismutase-mimic Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin (Mn(III)TMpyP), the hydrogen peroxide-scavenger catalase and the electron donor nicotinamide adenine dinucleotido phosphate (NADPH). PQ only was found to induce structural chromosomal damage in cultured anuran leukocytes in a dose-dependent manner. PQ plus NADPH, which served as positive control, enhanced the genotoxic effect of PQ. Dl-α-tocopherol only did not induce any structural chromosomal damage in the leukocytes. PQ plus dl-α-tocopherol, however, enhanced the genotoxic effect of PQ. PQ plus Mn(III)TMpyP, PQ plus catalase and PQ plus Mn(III)TMpyP plus catalse suppressed the genotoxic effect of PQ. Furthermore, PQ plus dl-α-tocopherol-enhanced chromosomal damage was also inhibited by Mn(III)TMpyP plus catalase. These results suggest that dl-α-tocopherol in combination with PQ functions as an electron donor to PQ.
authors.affiliation: Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashihiroshima, Japan. hanada@hiroshima-u.ac.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Hanada
mesh_terms: D000818:Animals; D001001:Anura / Q000097:blood*; D002374:Catalase / Q000494:pharmacology; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D006540:Herbicides / Q000633:toxicity*; D007962:Leukocytes / Q000187:drug effects*; D008665:Metalloporphyrins / Q000494:pharmacology; D009152:Mutagenicity Tests / Q000379:methods; D009249:NADP / Q000494:pharmacology; D010269:Paraquat / Q000633:toxicity*; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D006540:Herbicides; D008665:Metalloporphyrins; D009249:NADP; C050950:tetrakis(N-methyl-4-pyridiniumyl)porphine manganese(III) complex; D002374:Catalase; D024502:alpha-Tocopherol; D010269:Paraquat