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Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions

Biotransformation may substantially reduce the extent to which organic environmental contaminants accumulate in fish. Presently, however, relatively little is known regarding the biotransformation of ionized chemicals, including cationic surfactants, in aquatic organisms. To address this deficiency,...

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Autores principales: Droge, Steven T.J., Armitage, James M., Arnot, Jon A., Fitzsimmons, Patrick N., Nichols, John W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9187044/
https://www.ncbi.nlm.nih.gov/pubmed/34379820
http://dx.doi.org/10.1002/etc.5189
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author Droge, Steven T.J.
Armitage, James M.
Arnot, Jon A.
Fitzsimmons, Patrick N.
Nichols, John W.
author_facet Droge, Steven T.J.
Armitage, James M.
Arnot, Jon A.
Fitzsimmons, Patrick N.
Nichols, John W.
author_sort Droge, Steven T.J.
collection PubMed
description Biotransformation may substantially reduce the extent to which organic environmental contaminants accumulate in fish. Presently, however, relatively little is known regarding the biotransformation of ionized chemicals, including cationic surfactants, in aquatic organisms. To address this deficiency, a rainbow trout liver S9 substrate depletion assay (RT‐S9) was used to measure in vitro intrinsic clearance rates (CL(int); ml min(–1) g liver(–1)) for 22 cationic surfactants that differ with respect to alkyl chain length and degree of methylation on the charged nitrogen atom. None of the quaternary N,N,N‐trimethylalkylammonium compounds exhibited significant clearance. Rapid clearance was observed for N,N‐dimethylalkylamines, and slower rates of clearance were measured for N‐methylalkylamine analogs. Clearance rates for primary alkylamines were generally close to or below detectable levels. For the N‐methylalkylamines and N,N‐dimethylalkylamines, the highest CL(int) values were measured for C(10)–C(12) homologs; substantially lower clearance rates were observed for homologs containing shorter or longer carbon chains. Based on its cofactor dependency, biotransformation of C(12)–N,N‐dimethylamine appears to involve one or more cytochrome P450–dependent reaction pathways, and sulfonation. On a molar basis, N‐demethylation metabolites accounted for up to 25% of the N,N‐dimethylalkylamines removed during the 2‐h assay, and up to 55% of the removed N‐methylalkylamines. These N‐demethylation products possess greater metabolic stability in the RT‐S9 assay than the parent structures from which they derive and may contribute to the overall risk of ionizable alkylamines. The results of these studies provide a set of consistently determined CL(int) values that may be extrapolated to whole trout to inform in silico bioaccumulation assessments. Environ Toxicol Chem 2021;40:3123–3136. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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spelling pubmed-91870442022-10-14 Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions Droge, Steven T.J. Armitage, James M. Arnot, Jon A. Fitzsimmons, Patrick N. Nichols, John W. Environ Toxicol Chem Environmental Toxicology Biotransformation may substantially reduce the extent to which organic environmental contaminants accumulate in fish. Presently, however, relatively little is known regarding the biotransformation of ionized chemicals, including cationic surfactants, in aquatic organisms. To address this deficiency, a rainbow trout liver S9 substrate depletion assay (RT‐S9) was used to measure in vitro intrinsic clearance rates (CL(int); ml min(–1) g liver(–1)) for 22 cationic surfactants that differ with respect to alkyl chain length and degree of methylation on the charged nitrogen atom. None of the quaternary N,N,N‐trimethylalkylammonium compounds exhibited significant clearance. Rapid clearance was observed for N,N‐dimethylalkylamines, and slower rates of clearance were measured for N‐methylalkylamine analogs. Clearance rates for primary alkylamines were generally close to or below detectable levels. For the N‐methylalkylamines and N,N‐dimethylalkylamines, the highest CL(int) values were measured for C(10)–C(12) homologs; substantially lower clearance rates were observed for homologs containing shorter or longer carbon chains. Based on its cofactor dependency, biotransformation of C(12)–N,N‐dimethylamine appears to involve one or more cytochrome P450–dependent reaction pathways, and sulfonation. On a molar basis, N‐demethylation metabolites accounted for up to 25% of the N,N‐dimethylalkylamines removed during the 2‐h assay, and up to 55% of the removed N‐methylalkylamines. These N‐demethylation products possess greater metabolic stability in the RT‐S9 assay than the parent structures from which they derive and may contribute to the overall risk of ionizable alkylamines. The results of these studies provide a set of consistently determined CL(int) values that may be extrapolated to whole trout to inform in silico bioaccumulation assessments. Environ Toxicol Chem 2021;40:3123–3136. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. John Wiley and Sons Inc. 2021-09-21 2021-11 /pmc/articles/PMC9187044/ /pubmed/34379820 http://dx.doi.org/10.1002/etc.5189 Text en © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC https://creativecommons.org/licenses/by-nc/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Environmental Toxicology
Droge, Steven T.J.
Armitage, James M.
Arnot, Jon A.
Fitzsimmons, Patrick N.
Nichols, John W.
Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions
title Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions
title_full Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions
title_fullStr Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions
title_full_unstemmed Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions
title_short Biotransformation Potential of Cationic Surfactants in Fish Assessed with Rainbow Trout Liver S9 Fractions
title_sort biotransformation potential of cationic surfactants in fish assessed with rainbow trout liver s9 fractions
topic Environmental Toxicology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9187044/
https://www.ncbi.nlm.nih.gov/pubmed/34379820
http://dx.doi.org/10.1002/etc.5189
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