Reference : Approaches for assessing potential impacts of thyroid hormone disrupting chemicals in wi...

	Document type :	Scientific congresses and symposiums : Poster
	Discipline(s) :	Life sciences : Aquatic sciences & oceanology
	To cite this reference:	http://hdl.handle.net/2268/75057

Title :	Approaches for assessing potential impacts of thyroid hormone disrupting chemicals in wild sea bass (Dicentrarchus labrax)
Language :	English
Author, co-author :	Schnitzler, Joseph [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Océanologie >]
	Klaren, Peter [ > > ]
	Thomé, Jean-Pierre [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Ecologie animale et écotoxicologie >]
	Das, Krishna [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Océanologie >]
Publication date :	2010
Audience :	International
Event name :	SETAC Europe: 20th Annual Meeting
Event organizer :	SETAC
Event place (city) :	Sevilla
Event country :	Espagne
Keywords :	[en] Thyroid ; endocrine disruption ; sea bass
Abstract :	[en] Organic compounds such as pesticides and polychlorobiphenyls (PCBs) are well described endocrine disrupters; of particular interest are effects on thyroid function. To assess the ability of occurring pollutants in European coastal areas to disrupt the thyroid system in sea bass, a field study in the major European estuaries, namely, the Scheldt, the Seine, the Loire, the Charente and the Garonne has been conducted. Several thyroid endpoints were simultaneously examined. Diameter of follicles and the epithelial cell heights give an indication on the production and secretion activity of the thyroid gland. The activity of enzymes involved in the metabolism (deiodination, glucuronidation and sulfatation) of thyroid hormones was analyzed. Finally thyroxine (T4) and triiodothyronine (T3) concentrations were analyzed in muscle by radioimmunoassay. The combined use of all those endpoints gives us an overview of the complex thyroid hormone system. PCB concentration in wild fish varied from 10 to 100 ng g-1 wet weight (ww) depending on length and location. Each region has its own contamination levels and profiles reflecting the contribution of pollutants from rivers. The contamination levels were as follows: the highest concentrations were measured in individuals collected from the coastal region near the Scheldt > Seine > Loire > Charente and the lowest levels were observed in sea bass from coastal regions near the Garonne. Measurements of metabolic activity revealed an altered hepatic T4 outer ring deiodinase whereas T4 sulfatation and T4 glucuronidation were not affected. Owing to the extensive autoregulatory feedback at both central and peripheral levels, the thyroid hormone concentrations were preserved despite the PCB induced changes in thyroid hormone dynamics.
Research units :	Centre Interfacultaire de Recherches en Océanologie - MARE
Funders :	Fonds pour la formation à la Recherche dans l'Industrie et dans l'Agriculture (Communauté française de Belgique) - FRIA
Target :	Researchers ; Professionals ; Students ; General public ; Others
Permalink :	http://hdl.handle.net/2268/75057

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