title: Carcinogenicity and genotoxicity of the herbicide 2,4,5-trichlorophenoxyethanol (TCPE) contaminated with dioxin.
abstract: In an earlier study 2,4,5-trichlorophenoxythanol (TCPE) contaminated with dioxin, a component of the Hungarian herbicide Buvinol, was found to be hepatocarcinogenic. In the present work, the hepatocarcinogenicity of TCPE was compared to its possible genotoxicity in vitro, using the Salmonella/microsome test for mutagenicity and for its DNA-damaging effect, the induction of sister chromatid exchanges (SCE) in Chinese hamster cells in vitro. It was found that purified TCPE (with 0.1 ppm dioxin content) was under no conditions mutagenic by the Ames test, i.e., it belongs to the group of false-negative chemicals. TCPE was, however, genotoxic; its DNA-damaging effect was demonstrated by an increase in the frequency of SCE, while pure dioxin of corresponding amount was ineffective. However, elevated SCE frequency and the toxicity on bacteria and mammalian cells by TCPE were significantly decreased by the metabolic activation system (S-9 mix) isolated from liver. This observation indicates that in the detoxication of TCPE in vitro, a key role is to be attributed to the hepatic microsomal enzymes. It is presumed that TCPE is hepatocarcinogenic only in a dose range which has exhausted the detoxicating capacity of the liver.
authors.affiliation: National Institute of Oncology, Research Institute of Oncopathology, Budapest, Hungary.
authors.forename: J
authors.initials: J
authors.lastname: Sugár
authors.forename: K
authors.initials: K
authors.lastname: Tóth
authors.forename: E
authors.initials: E
authors.lastname: Oláh
mesh_terms: D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000633:toxicity; D000818:Animals; D006224:Cricetinae; D004147:Dioxins; D004305:Dose-Response Relationship, Drug; D004340:Drug Contamination; D008113:Liver Neoplasms / Q000139:chemically induced; D008297:Male; D051379:Mice; D009152:Mutagenicity Tests; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity; D051381:Rats; D011919:Rats, Inbred Strains; D012854:Sister Chromatid Exchange / Q000187:drug effects
chemical_list: D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; C016796:2,4,5-trichlorophenoxyethanol; D015085:2,4,5-Trichlorophenoxyacetic Acid