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2nd Norwegian Environmental Toxicology Symposium: joining forces for an integrated search for environmental solutions.

https://arctichealth.org/en/permalink/ahliterature90204
Source
J Toxicol Environ Health A. 2009;72(3-4):111
Publication Type
Article
Date
2009

Biotransformation of PCBs in relation to phase I and II xenobiotic-metabolizing enzyme activities in ringed seals (Phoca hispida) from Svalbard and the Baltic Sea.

https://arctichealth.org/en/permalink/ahliterature90147
Source
Environ Sci Technol. 2008 Dec 1;42(23):8952-8
Publication Type
Article
Date
Dec-1-2008
Author
Routti Heli
Letcher Robert J
Arukwe Augustine
Van Bavel Bert
Yoccoz Nigel G
Chu Shaogang
Gabrielsen Geir W
Author Affiliation
Norwegian Polar Institute, Polar Environmental Centre, 9296 Tromsø, Norway. heli.routti@npolar.no
Source
Environ Sci Technol. 2008 Dec 1;42(23):8952-8
Date
Dec-1-2008
Language
English
Publication Type
Article
Keywords
Animals
Biotransformation
Environmental monitoring
Female
Liver - enzymology
Male
Metabolic Detoxication, Phase I
Metabolic Detoxication, Phase II
Oceans and Seas
Phoca - metabolism
Polychlorinated Biphenyls - analysis - pharmacokinetics
Principal Component Analysis
Species Specificity
Svalbard
Xenobiotics - metabolism
Abstract
Polychlorinated biphenyls (PCBs) may induce activity of hepatic enzymes, mainly Phase I monooxygenases and conjugating Phase II enzymes, that catalyze the metabolism of PCBs leading to formation of metabolites and to potential adverse health effects. The present study investigates the concentration and pattern of PCBs, the induction of hepatic phase I and II enzymes, and the formation of hydroxy (OH) and methylsulfonyl (CH3SO2=MeSO2) PCB metabolites in two ringed seal (Phoca hispida) populations, which are contrasted by the degree of contamination exposure, that is, highly contaminated Baltic Sea (n=31) and less contaminated Svalbard (n=21). Phase I enzymes were measured as ethoxyresorufin-O-deethylation (EROD), benzyloxyresorufin-O-dealkylation (BROD), methoxyresorufin-O-demethylation (MROD), and pentoxyresorufin-O-dealkylation (PROD) activities, and phase II enzymes were measured as uridine diphosphophate glucuronosyl transferase (UDPGT) and glutathione-S-transferase (GST). Geographical comparison, multivariate, and correlation analysis indicated that sigma-PCB had a positive impact on Phase I enzyme and GST activities leading to biotransformation of group III (vicinal ortho-meta-H atoms and
PubMed ID
19192824 View in PubMed
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Hepatic retention and toxicological responses during feeding and depuration periods in Atlantic salmon ( Salmo salar ) fed graded levels of the synthetic antioxidant, butylated hydroxytoluene.

https://arctichealth.org/en/permalink/ahliterature91272
Source
J Agric Food Chem. 2008 Dec 10;56(23):11540-9
Publication Type
Article
Date
Dec-10-2008
Author
Holaas Eivind
Bohne Victoria B
Hamre Kristin
Arukwe Augustine
Author Affiliation
Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
Source
J Agric Food Chem. 2008 Dec 10;56(23):11540-9
Date
Dec-10-2008
Language
English
Publication Type
Article
Keywords
Animal Feed - analysis
Animals
Antioxidants - chemical synthesis - metabolism - toxicity
Butylated Hydroxytoluene - chemical synthesis - metabolism - toxicity
Eating
Fish Proteins - genetics - metabolism
Gene Expression - drug effects
Liver - chemistry - drug effects - metabolism
Salmo salar - genetics - physiology
Abstract
The human safety aspects of seafood production require the expansion of vital knowledge of both nutrients and possible contaminants along the entire production chain. Thus, production of safer seafood can be achieved by using feed materials that are low in contaminants, while maintaining balanced nutrition, in order to secure optimal fish and consumer health. Our understanding of primary responses of fish health and production related diseases, as well as biological processes that influence carry-over and lowering of contaminants in farmed fish, will contribute to a sustainable production of safer seafood products. Therefore, we have studied the liver deposition and toxicological effects in salmon fed graded levels of BHT during a 12-week feeding followed by a 2-week depuration period using chemical, molecular, and catalytic assays. In general, our data showed that BHT was significantly retained in the liver and selectively modulated toxicological responses in the xenobiotic biotransformation pathways during the feeding period. Specifically, BHT produced consistent dose- and time-specific gene expression patterns for AhR2alpha, AhR2beta, CYP1A1, CYP3A, UGT1, and GSTpi. The effect of BHT on the gene expression of biotransformation enzyme did not parallel enzyme activity levels, suggesting a possible inhibition by parent BHT or its metabolites. As a safety precaution, the production of farmed Atlantic salmon in Norway requires a mandatory 2-week depuration period prior to slaughtering and market delivery to ensure the elimination of veterinary medicaments, additives, and other undesirable components. Comparison of feeding and depuration periods showed that BHT was highly retained in fish liver, as only 8-13% of fed BHT was eliminated during the 2-week depuration period. This is just a part of the total concentration in the whole fish, since BHT may have been distributed and accumulated in other organs. Since BHT or its metabolites putatively inhibited biotransformation enzymes and affected metabolism of the compound, they may have potential for toxicological and adverse health effects for both fish and fish consumers through carry-over processes from the fish products.
PubMed ID
19007167 View in PubMed
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Recombinant transthyretin purification and competitive binding with organohalogen compounds in two gull species (Larus argentatus and Larus hyperboreus).

https://arctichealth.org/en/permalink/ahliterature91094
Source
Toxicol Sci. 2009 Feb;107(2):440-50
Publication Type
Article
Date
Feb-2009
Author
Ucán-Marín Francisco
Arukwe Augustine
Mortensen Anne
Gabrielsen Geir W
Fox Glen A
Letcher Robert J
Author Affiliation
National Wildlife Research Centre, Carleton University, Ottawa, Ontario, K1A 0H3, Canada.
Source
Toxicol Sci. 2009 Feb;107(2):440-50
Date
Feb-2009
Language
English
Publication Type
Article
Keywords
Animals
Base Sequence
Binding, Competitive - drug effects
Brain Chemistry - physiology
Charadriiformes - metabolism
DNA, Complementary - biosynthesis - genetics
Environmental Pollutants - metabolism
Indicators and Reagents
Liver - metabolism
Molecular Sequence Data
Polybrominated Biphenyls - metabolism
Polychlorinated Biphenyls - metabolism
Prealbumin - isolation & purification - metabolism
RNA - biosynthesis - genetics
Recombinant Proteins - isolation & purification - metabolism
Reverse Transcriptase Polymerase Chain Reaction
Thyroxine - pharmacology
Triiodothyronine - pharmacology
Abstract
Glaucous gulls (Larus hyperboreus) from Svalbard, Norway (marine), and herring gulls (Larus argentatus) from the Laurentian Great Lakes (freshwater) of North America are differentially exposed to persistent and bioaccumulative anthropogenic contaminants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ether (PBDE) flame retardants and metabolic products. Such compounds can potentially perturb hormone transport via binding interactions with proteins such as transthyretin (TTR, prealbumin). In this present study, we isolated, cloned and sequenced TTR cDNA from the brain and liver of two species (herring and glaucous gull), which, to our knowledge, is the first report describing the TTR nucleic acid and amino acid sequences from any gull species. Identical TTR nucleotide and amino acid sequences were obtained from both gull species (liver and brain). Recombinant TTR (rTTR) was expressed and purified, and determined as a monomer of 18 kDa and homodimer of 36 kDa that putatively is comprised of the two protein monomers. Concentration dependent, competitive TTR-binding curves with each of the natural TTR ligands 3,5,3'-triiodothyronine (T(3)) and thyroxine (T(4)) were generated as well as by treatment with a range of concentrations (10(-3)-10(5)nM) of 2,2',3,4',5,5',6-heptaCB (CB187), 2,2',4,4'-tetrabromoDE (BDE47), and hydroxyl- (OH) and methoxyl (MeO)-containing analogs (i.e., 4-OH-CB187, 6-OH-BDE47, 4'-OH-BDE49, 4-MeO-CB187, and 6-MeO-BDE47). Relative to the nonsubstituted BDE47 and CB187 and their MeO-substituted analogs, the OH-substituted analogs all had lower K(i) and K(d) values, indicating greater affinity and more potent competitive binding to both T(3) and T(4). The OH-substitution position and/or the diphenyl ether substitution of the four bromine atoms resulted in more potent, greater affinity, and greater relative potency for 4'-OH-BDE49 relative to 6-OH-BDE47. CB187 was more comparable in binding potency and affinity to 4-OH-CB187, then was 6-OH-BDE47 and 4'-OH-BDE49 relative to BDE47 where the binding potency and affinity was several orders of magnitude greater for 6-OH-BDE47 and 4'-OH-BDE49. This indicated that the combination of the more thyroid hormone-like brominated diphenyl ether backbone (relative to the chlorinated biphenyl backbone), and in combination of having an OH-group, results in a more effective competitive ligand on gull TTR relative to both T(3) and T(4). Known circulating levels of 4-OH-CB187, 6-OH-BDE47, and 4'-OH-BDE49 in the plasma of free-ranging Svalbard glaucous gulls were comparable to the concentration of in vitro competitive potency of T(3) and T(4) with gull TTR. These results suggest that environmentally relevant and selected OH-containing PCB, and to a lesser extent PBDE congeners have the potential to be physiologically effective in these gull species via perturbation of T(4) and T(3) transport.
PubMed ID
19033396 View in PubMed
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