Vg mRNA induction in an endangered fish species (Anguilla anguilla) from the Loire estuary (France)

• Published in: Ecotoxicology and Environmental Safety
• Main Authors: Blanchet-Letrouvé, Isabelle, Lafont, Anne-Gaëlle, Poirier, Laurence, Baloche, Sylvie, Zalouk-Vergnoux, Aurore, Dufour, Sylvie, Mouneyrac, Catherine
• 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), 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 2013
• Subjects: [SDE]Environmental Sciences; Anguilla anguilla; European eel
• Online Access: https://hal.science/hal-04654563; https://doi.org/10.1016/j.ecoenv.2013.07.019

International audience Estuarine zones are extremely fragile due to increasing stress from anthropogenic activities. Amongthose, the Loire estuary (France) is potentially exposed to various contaminants including EndocrineDisruptors Compounds (EDCs) able to impact the reproduction physiology of fish. The European eel(Anguilla anguilla), endangered fish species, is apparently not relevant, in its yellow stage, to monitor theeffects of endocrine disruption. Despite this weakly responsiveness, this study aimed to investigatewhether European eel from the Loire estuary may still be the subject of estrogenic disruption quantifyingthe hepatic Vg gene expression according to gender and sexual stage. Vitellogenin (Vg) appears as avaluable biomarker of EDCs, as well as for exposure and effects. Quantitative real-time ReverseTranscription Polymerase Chain Reaction (q RT PCR) was used in this study to amplify responses ofhepatic Vg transcripts. European eels were sampled in May 2009 (N¼57) and November 2010 (duringthe downstream migration, N¼10) in two sites of the Loire estuary with different ecological conditionsand contamination pressures (upstream: Varades; downstream: Nantes). Reproductive (gender, sexualmaturity stage) and biometric parameters of collected eels were determined. A laboratory exposure ofsilver male to steroid hormones (Testosterone (T), 11-KetoTestosterone (11-KT), Estradiol (E2)) wasconducted in parallel to validate the q RT PCR approach on hepatic Vg mRNA. Results demonstrated theresponsiveness of exposed silver male eels, since hepatic mRNA Vg induction was observed in E2 treatedmales compared to control specimens. In the field, results of female silver eels reflected large interindividual differences in the activation of hepatic Vg at silvering. However, while only female silver eelsshould express hepatic Vg mRNA, quantifiable levels were also detected in a proportion of 38% of theother individuals sampled, normally not inclined to express it, those being undifferentiated eels, yellowfemales, ...