title: Chiral PCB methyl sulfones in rat tissues after exposure to technical PCBs.
abstract: PCB methyl sulfones (MeSO2-PCBs) are lipophilic PCB metabolites known to exhibit selective tissue retention properties in wildlife and humans. The aim of this study was to investigate the presence of atropisomers of MeSO2-PCB congeners in tissues of rats exposed to a technical PCB product, Clophen A50. Changes in the enantiomer fractions (EFs) of the MeSO2-PCB atropisomers after exposure were also determined. Liver, lung, and adipose tissue from rats dosed with Clophen A50 were analyzed for the MeSO2-PCB atropisomers of 3-methylsulfonyl-2,2',4',5,6-pentachlorobiphenyl (5-MeSO2-CB91), 4-methylsulfonyl-2,2',3,4',6-pentachlorobiphenyl (4-MeSO2-CB91), 3-methylsulfonyl-2,2',3',4',5,6-hexachlorobiphenyl (5'-MeSO2-CB132), 4-methylsulfonyl-2,2',3,3',4',6-hexachlorobiphenyl (4'-MeSO2-CB132), 3-methylsulfonyl-2,2',4',5,5',6-hexachlorobiphenyl (5-MeSO2-CB149), and 4-methylsulfonyl-2,2',3,4',5',6-hexachlorobiphenyl (4-MeSO2-CB149). In all tissues analyzed, especially lung, the para-MeSO2-PCBs were more abundant than the meta-MeSO2-PCBs. The concentration ratio was higher for 4-MeSO2-CB149 versus 5-MeSO2-CB149 than for the corresponding ratio 4-/5-MeSO2-CB91 and 4'-/5'-MeSO2-CB132. Enantioselective MeSO2-PCB analysis of the lung samples showed an excess and dominance of the second eluting atropisomer of 4-MeSO2-CB149. In both lung and adipose tissues, small amounts of the first eluting atropisomer of 5-MeSO2-CB149 was present, but this atropisomer was not detected in the liver. No significant time-dependent changes in the EFs of 4-MeSO2-CB91, 5'-MeSO2-CB132, 4'-MeSO2-CB132, 5-MeSO2-CB149, and 4-MeSO2-CB149 atropisomers were found for either lung, liver, or adipose tissue. The results of the present study suggest that enantioselective formation occur for both meta- and para-MeSO2-PCBs.
authors.affiliation: Department of Environmental Chemistry, Stockholm University, Sweden. Christina.Larsson@mk.su.se
authors.forename: Christina
authors.initials: C
authors.lastname: Larsson
authors.forename: Thomas
authors.initials: T
authors.lastname: Ellerichmann
authors.forename: Heinrich
authors.initials: H
authors.lastname: Hühnerfuss
authors.forename: Ake
authors.initials: A
authors.lastname: Bergman
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D000818:Animals; D004785:Environmental Pollutants / Q000493:pharmacokinetics*; D007536:Isomerism; D008168:Lung / Q000737:chemistry; D008297:Male; D011078:Polychlorinated Biphenyls / Q000737:chemistry / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013450:Sulfones / Q000737:chemistry / Q000493:pharmacokinetics; D014018:Tissue Distribution
chemical_list: D004785:Environmental Pollutants; D013450:Sulfones; D011078:Polychlorinated Biphenyls