title: Comparative mutagenicity and toxic effects of 2,5,2',5'-tetrachlorobiphenyl and its metabolites in bacterial and mammalian test systems.
abstract: The possible toxicological properties of 2,5,2',5'-tetrachlorobiphenyl (TCB), 4-hydroxy-2,5,2',5'-tetrachlorobiphenyl (TCB-OH), and 2,5,2',5'-tetrachlorobiphenyl-3,4-oxide (TCB-oxide) were evaluated in three bioassay systems. Incubation of rat hepatocyte plasma membranes with 50 microgram/ml of TCB-OH decreased the activity of Mg2+-ATPase by approximately 90%, whereas approximately half of the enzyme activity remained after the TCB or TCB-oxide treatment. All three compounds were found to be inactive in the Salmonella/microsome mutagenicity assay. Only TCB-OH possessed potent cytotoxic activity against all four S. tymphimurium strains tested. It affects the viability of TA 1537 by as much as 40% even at concentrations as low as 1 microgram/ml. These data suggest the potential toxicological significance of metabolic activation by the hepatic microsomal mixed-function oxidases.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002478:Cells, Cultured; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D009153:Mutagens; D011078:Polychlorinated Biphenyls / Q000494:pharmacology* / Q000633:toxicity; D051381:Rats; D012486:Salmonella typhimurium / Q000187:drug effects
chemical_list: D009153:Mutagens; D011078:Polychlorinated Biphenyls; D000251:Adenosine Triphosphatases