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Effects of a Glucocorticoid Receptor Agonist, Dexamethasone, on Fathead Minnow Reproduction, Growth, and Development.
Citation:
LALONE, C. A., DAN VILLENEUVE, A. W. OLMSTEAD, E. K. MEDLOCK, M. D. KAHL, K. M. JENSEN, E. J. DURHAN, L. A. MAKYNEN, C. A. BLANKSMA, J. E. CAVALLIN, L. M. THOMAS, S. M. SEIDL, S. Y. SKOLNESS, L. C. WEHMAS, R. D. JOHNSON, AND G. T. ANKLEY. Effects of a Glucocorticoid Receptor Agonist, Dexamethasone, on Fathead Minnow Reproduction, Growth, and Development. . ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 31(3):611-622, (2012).
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Description:
Few studies have examined the effects of synthetic glucocorticoids on the reproductive axis of fish, despite the fact that these chemicals are therapeutically prescribed anti-inflammatory agents that are abundantly produced and consumed. To generate data to assess potential risk to the aquatic environment, we used fathead minnow 21 day reproduction and 29 day embryo/larvae assays to determine reproductive toxicity and early life stage effects of the common human and veterinary drug, dexamethasone. Exposure to 500 µg dexamethasone/L in the 21-d test caused reductions in fathead minnow fecundity and female plasma estradiol concentrations, and increased the occurrence of abnormally hatched fry. Female fish exposed to 500 µg dexamethasone/L also displayed a significant increase in plasma vitellogenin (vtg) protein levels possibly due to decreased spawning. A decrease in vtg mRNA expression in liver tissue from females exposed to the high dexamethasone concentration lends support to this hypothesis. Concentrations of 0.1 and 50 µg dexamethasone/L significantly increased both gonad mass and gonadal somatic index for males and females. Histological results indicate that 29 day embryo/larvae exposure to 500 µg dexamethasone/L caused a significant increase in deformed gill opercula. Fry exposed to 500 µg dexamethasone/L for 29 days also exhibited a significant reduction in weight and length compared to control fry. Taken together these results indicate that non-lethal concentrations of a model glucocorticoid receptor agonist can impair fish reproduction, growth and development.