title: ABC transporters and xenobiotic defense systems in early life stages of rainbow trout (Oncorhynchus mykiss).
abstract: Embryos of oviparous fish, in contrast to (ovo) viviparous species, develop in the aquatic environment, and therefore need solute transport systems at their body surfaces for maintaining internal homeostasis and defending against potentially harmful substances. We hypothesized that solute transporters undergo changes in tissue distribution from the embryo to the larval stage. We therefore studied the mRNA profiles of eight ABC transporters (abcb1a, abcb1b, abcc1, abcc2, abcc3, abcc4, abcc5, abcg2) and three solute carriers (oatp1d, putative oatp2 putative, mate1) in different body regions (head, yolk sac epithelium, abdominal viscera, skin/muscles) of developing rainbow trout. Additionally, we investigated mRNA levels of phase I (cyp1a, cyp3a) and phase II (gstp, putative ugt1, putative ugt2) biotransformation enzymes. The study covered the developmental period from the eleuthero-embryo stage to the first-feeding larval stage (1-20days post-hatch, dph). At 1dph, transcripts of abcc2, abcc4, abcg2, cyp3a, gstp, putative mate1, and putative oatp2 occurred primarily in the yolk sac epithelium, whereas at later stages expression of these genes was predominantly observed in the abdominal viscera. The functional activity of ABC transporters in fish early life stages was assessed by rhodamine B accumulation assays. Finally, we investigated the potential impact of xenobiotics (clotrimazole, clofibric acid) on the ABC and biotransformation systems of trout early life stages. While clofibric acid had no effect, clotrimazole lead to an increased rhodamine B accumulation. The results provide evidence that the transition from the eleuthero-embryo to the larval stage is accompanied by a major alteration in tissue expression of ABC transporters.
authors.affiliation: University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland; Centre for Fish and Wildlife Health, University of Bern, Länggassstrasse 122, CH-3012 Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Kropf
authors.affiliation: Centre for Fish and Wildlife Health, University of Bern, Länggassstrasse 122, CH-3012 Bern, Switzerland.
authors.forename: Helmut
authors.initials: H
authors.lastname: Segner
authors.affiliation: University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland; Swiss Federal Institute of Technology, ETH Zürich, Institute of Biogeochemistry and Pollution Dynamics, CH-8092 Zürich. Electronic address: karl.fent@fhnw.ch.
authors.forename: Karl
authors.initials: K
authors.lastname: Fent
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000222:Adaptation, Physiological; D000818:Animals; D002994:Clofibrate / Q000494:pharmacology; D003022:Clotrimazole / Q000494:pharmacology; D005260:Female; D029941:Fish Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007814:Larva / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012235:Rhodamines / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D029941:Fish Proteins; D012333:RNA, Messenger; D012235:Rhodamines; D003022:Clotrimazole; D002994:Clofibrate; C029773:rhodamine B
keywords: ABC transporter; Biotransformation; Early life stage; Oncorhynchus mykiss; Solute carriers; Yolk sac