title: Effects of a glucocorticoid receptor agonist, dexamethasone, on fathead minnow reproduction, growth, and development.
abstract: Synthetic glucocorticoids are pharmaceutical compounds prescribed in human and veterinary medicine as anti-inflammatory agents and have the potential to contaminate natural watersheds via inputs from wastewater treatment facilities and confined animal-feeding operations. Despite this, few studies have examined the effects of this class of chemicals on aquatic vertebrates. To generate data to assess potential risk to the aquatic environment, we used fathead minnow 21-d reproduction and 29-d embryo-larvae assays to determine reproductive toxicity and early-life-stage effects of 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 protein levels, possibly because of decreased spawning. A decrease in vitellogenin messenger ribonucleic acid (mRNA) expression in liver tissue from females exposed to the high dexamethasone concentration lends support to this hypothesis. Histological results indicate that a 29-d embryo-larval exposure to 500 µg dexamethasone/L caused a significant increase in deformed gill opercula. Fry exposed to 500 µg dexamethasone/L for 29 d also exhibited a significant reduction in weight and length compared with control fry. Taken together, these results indicate that nonlethal concentrations of a model glucocorticoid receptor agonist can impair fish reproduction, growth, and development.
authors.affiliation: Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, U.S. Environmental Protection Agency, Duluth, Minnesota, USA. LaLone.Carlie@epa.gov
authors.forename: Carlie A
authors.initials: CA
authors.lastname: LaLone
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Villeneuve
authors.forename: Allen W
authors.initials: AW
authors.lastname: Olmstead
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Medlock
authors.forename: Michael D
authors.initials: MD
authors.lastname: Kahl
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Jensen
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Durhan
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Makynen
authors.forename: Chad A
authors.initials: CA
authors.lastname: Blanksma
authors.forename: Jenna E
authors.initials: JE
authors.lastname: Cavallin
authors.forename: Linnea M
authors.initials: LM
authors.lastname: Thomas
authors.forename: Sara M
authors.initials: SM
authors.lastname: Seidl
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Skolness
authors.forename: Leah C
authors.initials: LC
authors.lastname: Wehmas
authors.forename: Rodney D
authors.initials: RD
authors.lastname: Johnson
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Ankley
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000633:toxicity; D003530:Cyprinidae; D003907:Dexamethasone / Q000633:toxicity*; D004625:Embryo, Nonmammalian / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D005260:Female; D005298:Fertility; D048788:Growth and Development / Q000187:drug effects*; D008297:Male; D011965:Receptors, Glucocorticoid / Q000819:agonists*; D012098:Reproduction / Q000187:drug effects*; D014819:Vitellogenins / Q000097:blood; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000893:Anti-Inflammatory Agents; D011965:Receptors, Glucocorticoid; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D004958:Estradiol; D003907:Dexamethasone