title: Assessment of estrogenic exposure in brown trout (Salmo trutta) in a Swiss midland river: integrated analysis of passive samplers, wild and caged fish, and vitellogenin mRNA and protein.
abstract: This field study examined the vitellogenin (VTG) biomarker response under conditions of low and fluctuating activities of environmental estrogenicity. The present study was performed on immature brown trout (Salmo trutta) exposed to the small river Luetzelmurg, which is located in the prealpine Swiss midland region and receives effluents from a single sewage treatment plant (STP). To understand better factors influencing the relationship between estrogenic exposure and VTG induction, we compared VTG levels in caged (stationary) and feral (free-ranging) fish, VTG levels in fish from up- and downstream of the STP, and two different methods for quantifying VTG (enzyme-linked immunosorbent assay vs real-time reverse transcription-polymerase chain reaction), and we used passive samplers (polar organic chemical integrative sampler [POCIS]) to integrate the variable, bioaccumulative estrogenic load in the river water over time. The POCIS from the downstream site contained approximately 20-fold higher levels of bioassay-derived estrogen equivalents than the POCIS from the upstream site. In feral fish, this site difference in estrogenic exposure was reflected in VTG protein levels but not in VTG mRNA. In contrast, in caged fish, the site difference was evident only for VTG mRNA but not for VTG protein. Thus, the outcome of VTG biomarker measurements varied with the analytical detection method (protein vs mRNA) and with the exposure modus (caged vs feral). Our findings suggest that for environmental situations with low and variable estrogenic contamination, a multiple-assessment approach may be necessary for the assessment of estrogenic exposure in fish.
authors.affiliation: Centre for Fish and Wildlife Health, University of Bern, Länggassstrasse 122, CH-3001 Bern, Switzerland. richard.burki@itpa.unibe.ch
authors.forename: Richard
authors.initials: R
authors.lastname: Burki
authors.forename: Etiënne L M
authors.initials: EL
authors.lastname: Vermeirssen
authors.forename: Oliver
authors.initials: O
authors.lastname: Körner
authors.forename: Caroline
authors.initials: C
authors.lastname: Joris
authors.forename: Patricia
authors.initials: P
authors.lastname: Burkhardt-Holm
authors.forename: Helmut
authors.initials: H
authors.lastname: Segner
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D052244:Endocrine Disruptors / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D004967:Estrogens / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013557:Switzerland; D014337:Trout; D014819:Vitellogenins / Q000235:genetics / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000494:pharmacology*
chemical_list: D017931:DNA Primers; D052244:Endocrine Disruptors; D004967:Estrogens; D012333:RNA, Messenger; D014819:Vitellogenins; D014874:Water Pollutants, Chemical