title: Age-related mercury contamination and relationship with luteinizing hormone in a long-lived Antarctic bird.
abstract: Seabirds, as long-lived top predators, accumulate contaminants such as mercury (Hg), an established endocrine disruptor. In long lived species hormonal secretion varies with age; therefore, Hg-induced endocrine disruption may be exacerbated in some age classes. Here we investigated relationships between blood total Hg and luteinizing hormone (LH, a key pituitary hormone for the onset of breeding), in pre-laying known-age (11-45 years old) snow petrels (Pagodroma nivea) from Adélie Land, Antarctica. We predicted that 1) blood Hg would increase with advancing age as a consequence of bio-accumulation; and that 2) increasing blood Hg would be related to decreased concentrations of LH in the most Hg-contaminated individuals. Hg concentrations were higher in females than in males (p<0.001), and contrary to our prediction, decreased with advancing age in males (p = 0.009) and tended to do so in females (p = 0.06). The analysis of stable isotopes (δ13C and δ15N) suggested that this unexpected pattern could originate from age and sex-related variations in trophic niche, and hence Hg exposure. Regarding LH, our prediction was only supported in young birds (≤23 years) where baseline LH was inversely correlated with Hg concentrations (p = 0.04). Hg burden did not predict baseline LH or GnRH-induced LH in birds that were more than 23 years old. These results show that age and contaminants may interfere with major endocrine mechanisms and, together with other recent studies, support the view that Hg could be connected to LH secretion and could then impair the fitness of long-lived birds.
authors: Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de la Rochelle, Villiers-en-Bois, France.
authors: Sabrina
authors: S
authors: Tartu
authors: Littoral Environnement Société (LIENSs), UMR 7266 CNRS-Université La Rochelle, La Rochelle, France.
authors: Paco
authors: P
authors: Bustamante
authors: Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de la Rochelle, Villiers-en-Bois, France.
authors: Aurélie
authors: A
authors: Goutte
authors: Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de la Rochelle, Villiers-en-Bois, France.
authors: Yves
authors: Y
authors: Cherel
authors: Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de la Rochelle, Villiers-en-Bois, France.
authors: Henri
authors: H
authors: Weimerskirch
authors: Norwegian Institute for Nature Research, FRAM - High North Research Centre on Climate and the Environment, Tromsø, Norway.
authors: Jan Ove
authors: JO
authors: Bustnes
authors: Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 CNRS-Université de la Rochelle, Villiers-en-Bois, France.
authors: Olivier
authors: O
authors: Chastel
mesh_terms: D000367:Age Factors; D000375:Aging / Q000187:drug effects*; D000818:Animals; D000864:Antarctic Regions; D001717:Birds / Q000378:metabolism*; D004785:Environmental Pollutants / Q000633:toxicity; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D008628:Mercury / Q000633:toxicity*; D012737:Sex Factors
chemical_list: D004785:Environmental Pollutants; D007986:Luteinizing Hormone; D008628:Mercury