title: Effects of model aromatizable (17α-methyltestosterone) and non-aromatizable (5α-dihydrotestosterone) androgens on the adult mummichog (Fundulus heteroclitus) in a short-term reproductive endocrine bioassay.
abstract: Androgens originating from pulp mill processing, sewage treatment facilities and agricultural activities have the potential for discharge into aquatic receiving environments. To assess androgen effects on reproductive endocrine status in fish in estuarine environments, male and female adult northern mummichog (Fundulus heteroclitus macrolepidotus) were exposed to an aromatizable androgen (17α-methyltestosterone; MT) and a non-aromatizable androgen (5α-dihydrotestosterone; DHT) in a short-term reproductive endocrine bioassay. Fish were nominally exposed to 10 μg/L or 100 μg/L DHT, or 0.1 μg/L or 1 μg/L MT for 14 days during gonadal recrudescence. Actual concentrations of androgens, as measured by enzyme immunoassay (EIA), were 10-49% of nominal MT 0.1, 3-6% of nominal MT 1, 5-10% of nominal DHT 10 and 3-25% of nominal DHT 100. Female mummichog were impacted to a greater degree by androgen exposure, with increased plasma testosterone (T) at 100 μg/L DHT, depressed plasma 17β-estradiol (E2) at both DHT concentrations and at 1 μg/L MT, as well as depressed in vitro E2 at both MT concentrations and 100 μg/L DHT. Males had depressed plasma T in the 10 μg/L DHT treatment and depressed in vitro 11-ketotestosterone production for both MT concentrations and 10 μg/L DHT. Ovarian aromatase gene expression was induced in females exposed to 1 μg/L MT. DHT at 100 μg/L increased hepatic vitellogenin-1 (VTG1) expression in males and depressed VTG1 expression in females. The range of responses between sexes and among species provides evidence for modes of actions and potential impacts of androgens in aquatic receiving environments.
authors: Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada. Electronic address: ruth4990@mylaurier.ca.
authors: Robert
authors: R
authors: Rutherford
authors: Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada.
authors: Andrea
authors: A
authors: Lister
authors: National Water Research Institute, Environment Canada, Burlington, ON L7R 4A6, Canada.
authors: L Mark
authors: LM
authors: Hewitt
authors: Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada.
authors: Deborah
authors: D
authors: MacLatchy
mesh_terms: D000367:Age Factors; D000728:Androgens / Q000633:toxicity*; D000818:Animals; D001681:Biological Assay / Q000379:methods; D013196:Dihydrotestosterone / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005260:Female; D023781:Fundulidae / Q000097:blood*; D008297:Male; D008777:Methyltestosterone / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D000728:Androgens; D014874:Water Pollutants, Chemical; D013196:Dihydrotestosterone; D008777:Methyltestosterone
keywords: Androgen; Dihydrotestosterone; Methyl testosterone; Mummichog; Reproductive endocrine