Thyroid endocrine status of wild European eels (Anguilla anguilla) in the Loire (France). Relationships with organic contaminant body burdens

• Published in: Science of The Total Environment
• Main Authors: Couderc, M., Marchand, J., Zalouk-Vergnoux, A., Kamari, A., Moreau, B., Blanchet-Letrouvé, I., Le Bizec, B., Mouneyrac, C., Poirier, L.
• Other Authors: Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), Laboratoire d'étude des Résidus et Contaminants dans les Aliments (LABERCA), École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Mer, molécules et santé (MMS UCO), Université Catholique de l'Ouest (UCO)-PRES Université Nantes Angers Le Mans (UNAM)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: [SDE]Environmental Sciences; Anguilla anguilla
• Online Access: https://hal.science/hal-04654552; https://doi.org/10.1016/j.scitotenv.2015.12.136

International audience In teleost fish, thyroid function is involved in various critical physiological processes. Given the complexity of thehypothalamo–pituitary–thyroid (HPT) axis, a large number of genes and proteins can be the potential target ofendocrine-disrupting compounds (EDCs). The aim of this study was to evaluate, in yellow and silver Europeaneels (Anguilla anguilla), potential effects of EDCs on thyroid status by analyzing the associations between EDCbody burdens and thyroid hormones (THs). In yellow individuals, greater free T3/T4 ratios (FT3/FT4) andlower plasma FT4 levels were associated with greater concentrations of polychlorinated biphenyls (PCBs) andpolybrominated diphenyl ethers (PBDEs), as highlighted by significant correlations with many congeners. Fewpositive relationships with alkylphenols were noticed. In contrast, silver eels usually exhibited less significantcorrelations between THs and contaminant loads. Expression of a series of genes involved in the HPT axis wasalso investigated in the silver individuals. Concerning mRNA expression in silver females, some main correlationswere noticed: thyroid-stimulating hormone (TSHβ) gene expression was significantly correlated to numerousPCBs, and hepatic mRNA levels of deiodinase 2 (Deio 2) were negatively correlated to 2-hydroxyfluorene (2-OHF) and 2-naphtol (2-OHNa). Thyroid receptor (TRα and TRβ) mRNA levels exhibited weak negative correlations with some PBDEs in silver females and males. Hepatic vitellogenin (Vtg) mRNA levels were detected in all silver males but at lower levels than in silver females. In males, Vtg mRNA levels were positively associated toFT4/TT4. In silver females, strong positive correlations were found between congeners of PCBs, PBDEs and PFASsuggesting potential estrogenic effects. Overall, the observed results indicate that several organic contaminants,mainly dl-, ndl-PCBs and PBDEs, could be associated with changes in thyroid homeostasis in these fish, via director indirect interactions with peripheral ...