title: Metabolism of clofibric acid in zebrafish embryos (Danio rerio) as determined by liquid chromatography-high resolution-mass spectrometry.
abstract: The zebrafish embryo (ZFE) is increasingly used in ecotoxicology research but detailed knowledge of its metabolic potential is still limited. This study focuses on the xenobiotic metabolism of ZFE at different life-stages using the pharmaceutical compound clofibric acid as study compound. Liquid chromatography with quadrupole-time-of-flight mass spectrometry (LC-QToF-MS) is used to detect and to identify the transformation products (TPs). In screening experiments, a total of 18 TPs was detected and structure proposals were elaborated for 17 TPs, formed by phase I and phase II metabolism. Biotransformation of clofibric acid by the ZFE involves conjugation with sulfate or glucuronic acid, and, reported here for the first time, with carnitine, taurine, and aminomethanesulfonic acid. Further yet unknown cyclization products were identified using non-target screening that may represent a new detoxification pathway. Sulfate containing TPs occurred already after 3h of exposure (7hpf), and from 48h of exposure (52hpf) onwards, all TPs were detected. The detection of these TPs indicates the activity of phase I and phase II enzymes already at early life-stages. Additionally, the excretion of one TP into the exposure medium was observed. The results of this study outline the high metabolic potential of the ZFE with respect to the transformation of xenobiotics. Similarities but also differences to other test systems were observed. Biotransformation of test chemicals in toxicity testing with ZFE may therefore need further consideration.
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research, UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Brox
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research, UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Seiwert
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research, UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Nora
authors.initials: N
authors.lastname: Haase
authors.affiliation: Department Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research, UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Küster
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research, UFZ, Permoserstrasse 15, 04318 Leipzig, Germany. Electronic address: thorsten.reemtsma@ufz.de.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Reemtsma
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D002995:Clofibric Acid / Q000378:metabolism* / Q000633:toxicity; D004625:Embryo, Nonmammalian / Q000378:metabolism; D050216:Metabolic Detoxication, Phase I; D050217:Metabolic Detoxication, Phase II; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization; D015027:Zebrafish / Q000196:embryology / Q000378:metabolism*
chemical_list: D002995:Clofibric Acid
keywords: Analytical chemistry; Drug metabolism; Environmental contaminants; Toxicity; Toxicokinetics; Xenobiotic