Mercury contamination impairs the hypothalamic-pituitary-adrenal axis of a neotropical caiman
Abstract
The capacity to regulate corticosterone release following a stressful event is an essential component of the physiological flexibility required to maintain homeostasis and ensure adaptive responses to environmental change. We show that wild smooth-fronted caimans with elevated blood mercury (Hg) concentrations exhibited reduced peak corticosterone levels during standardized stress tests, indicating a dampened maximal stress response. Hg blood concentrations were negatively correlated with corticosterone responsiveness, suggesting impairment of hypothalamic–pituitary–adrenal axis function. These results demonstrate that environmental Hg contamination is associated with reduced stress responsiveness and physiological flexibility, which likely limits the ability of Hg-contaminated individuals to cope with novel environmental stressors. We found that a methylmercury-sensitive cysteine in the glucocorticoid receptor is highly conserved across vertebrates, suggesting a shared molecular mechanism for mercury effects on glucocorticoid signaling. Given the widespread Hg pollution in tropical ecosystems, these findings emphasize the role of Hg as an endocrine-disrupting chemical in crocodylians.
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BibTeX
@article{lemaire2026mercury,
title = {{Mercury contamination impairs the hypothalamic-pituitary-adrenal axis of a neotropical caiman}},
author = {Jérémy Lemaire and Rosanna Mangione and Jasmine L. Loveland and Leonida Fusani and Virginie Canoine},
journal = {Communications Biology},
year = {2026},
month = oct,
doi = {10.1038/s42003-026-11022-0},
url = {https://www.nature.com/articles/s42003-026-11022-0},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Mercury contamination impairs the hypothalamic-pituitary-adrenal axis of a neotropical caiman
AU - Jérémy Lemaire
AU - Rosanna Mangione
AU - Jasmine L. Loveland
AU - Leonida Fusani
AU - Virginie Canoine
PY - 2026
DA - 2026/10/28
JO - Communications Biology
DO - 10.1038/s42003-026-11022-0
UR - https://www.nature.com/articles/s42003-026-11022-0
AB - The capacity to regulate corticosterone release following a stressful event is an essential component of the physiological flexibility required to maintain homeostasis and ensure adaptive responses to environmental change. We show that wild smooth-fronted caimans with elevated blood mercury (Hg) concentrations exhibited reduced peak corticosterone levels during standardized stress tests, indicating a dampened maximal stress response. Hg blood concentrations were negatively correlated with corticosterone responsiveness, suggesting impairment of hypothalamic–pituitary–adrenal axis function. These results demonstrate that environmental Hg contamination is associated with reduced stress responsiveness and physiological flexibility, which likely limits the ability of Hg-contaminated individuals to cope with novel environmental stressors. We found that a methylmercury-sensitive cysteine in the glucocorticoid receptor is highly conserved across vertebrates, suggesting a shared molecular mechanism for mercury effects on glucocorticoid signaling. Given the widespread Hg pollution in tropical ecosystems, these findings emphasize the role of Hg as an endocrine-disrupting chemical in crocodylians.
SN - 2399-3642
ER -