title: Blood levels of polychlorinated biphenyls and their hydroxylated metabolites in Baikal seals (Pusa sibirica): emphasis on interspecies comparison, gender difference and association with blood thyroid hormone levels.
abstract: We have previously demonstrated that Baikal seals (Pusa sibirica) are still being exposed to polychlorinated biphenyls (PCBs), and the population is at risk. In the present study, we measured the residue levels of PCBs and their hydroxylated metabolites (OH-PCBs) in the blood of Baikal seals and assessed the impact of OH-PCBs on the thyroid function. Blood concentrations of PCBs and OH-PCBs were in the range of 2.8-130 ng g(-1)wet wt. and 0.71-4.6 ng g(-1)wetwt., respectively. Concentrations of higher-chlorinated OH-PCBs (hexa- to octa-PCBs) were more than 70% to total OH-PCB concentrations, indicating Baikal seals are mostly risked by higher-chlorinated OH-PCBs. High levels of 4OH-CB146 and 4OH-CB187 and low levels of 4OH-CB107/4'OH-CB108 found in Baikal seals were different from those in other phocidae species, suggesting the unique drug-metabolizing enzyme activities and/or contamination sources in this species. Concentrations of some OH-PCBs in males were significantly higher than those in females. These results suggest that these isomers may be preferentially transferred from mother to pup via cord blood. However, concentrations of almost all the isomers were not significantly correlated with the levels of blood total T3 and T4, implying less impact of PCB-related compounds on the thyroid hormone circulation.
authors.affiliation: Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Imaeda
authors.affiliation: Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan. Electronic address: keinomi@agr.ehime-u.ac.jp.
authors.forename: Kei
authors.initials: K
authors.lastname: Nomiyama
authors.affiliation: Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kunisue
authors.affiliation: Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan.
authors.forename: Hisato
authors.initials: H
authors.lastname: Iwata
authors.affiliation: Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan.
authors.forename: Oyuna
authors.initials: O
authors.lastname: Tsydenova
authors.affiliation: Faculty of Fisheries, Nagasaki University, Bunkyo-cho 1-14, Nagasaki 852-8521, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Amano
authors.affiliation: The Eastern-Siberian Scientific and Production Fisheries Center, "VOSTSIBRYBCENTER", Ulan-Ude, Buryatia 670034, Russia.
authors.forename: Evgeny A
authors.initials: EA
authors.lastname: Petrov
authors.affiliation: Baikal Institute of Nature Management, Siberian Branch of Russian Academy of Sciences, Ulan-Ude, Buryatia 670047, Russia.
authors.forename: Valeriy B
authors.initials: VB
authors.lastname: Batoev
authors.affiliation: Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Tanabe
mesh_terms: D000818:Animals; D005260:Female; D006900:Hydroxylation; D008297:Male; D011078:Polychlorinated Biphenyls / Q000097:blood* / Q000378:metabolism; D046048:Seals, Earless / Q000097:blood* / Q000378:metabolism; D012737:Sex Factors; D013961:Thyroid Gland / Q000378:metabolism; D013963:Thyroid Hormones / Q000097:blood* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000097:blood* / Q000378:metabolism
chemical_list: D013963:Thyroid Hormones; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls
keywords: Baikal seals (Pusa sibirica); Hydroxylated PCBs (OH-PCBs); Metabolic capacity; Polychlorinated biphenyls (PCBs); Thyroid hormones (THs)