Chronic Exposure to Two Gestagens Differentially Alters Morphology and Gene Expression in Silurana tropicalis.

Thomson, Paisley; Pineda Castro, Marco A.; Yargeau, Viviane et Langlois, Valérie S. ORCID: https://orcid.org/0000-0003-4031-6838 (2021). Chronic Exposure to Two Gestagens Differentially Alters Morphology and Gene Expression in Silurana tropicalis. Archives of Environmental Contamination and Toxicology , vol. 80 , nº 4. pp. 745-759. DOI: 10.1007/s00244-021-00831-5.

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Résumé

Gestagens are active ingredients in human and veterinary drugs with progestogenic activity. Two gestagens—progesterone (P4), and the synthetic P4 analogue, melengestrol acetate (MGA)—are approved for use in beef cattle agriculture in North America. Both P4 and MGA have been measured in surface water receiving runoff from animal agricultural operations. This project aimed to assess the morphometric and molecular consequences of chronic exposures to P4, MGA, and their mixture during Western clawed frog metamorphosis. Chronic exposure (from embryo to metamorphosis) to MGA (1.7 µg/L) or P4 + MGA (0.22 µg/L P4 + 1.5 µg/L MGA) caused a considerable dysregulation of metamorphic timing, as evidenced by an inhibition of growth, narrower head, and lack of forelimb emergence in all animals. Molecular analysis revealed that chronic exposure to the mixture induced an additive upregulation of neurosteroid-related (GABAA receptor subunit α6 (gabra6) and steroid 5-alpha reductase 1 (srd5α1) gene expression in brain tissue. Chronic P4 exposure (0.26 µg/L P4) induced a significant upregulation of the expression hypothalamic–pituitary–gonadal (HPG)-related genes (ipgr, erα) in the gonadal mesonephros complex (GMC). Our data suggest that exposure to P4, MGA, and their mixture induces multiple endocrine responses and adverse effects in larval Western clawed frogs. This study helps to better our understanding of the consequences of chronic gestagen exposure and suggests that the implications and risk of high gestagen use in beef cattle feeding operations may extend to the aquatic environment.

Type de document:	Article
Mots-clés libres:	animals; cattle; gene expression; melengestrol acetate; north america; progesterone; progestins;
Centre:	Centre Eau Terre Environnement
Date de dépôt:	09 juin 2022 20:51
Dernière modification:	10 juin 2022 04:00
URI:	https://espace.inrs.ca/id/eprint/11772

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