title: Androgen disruption of early development in Qurt strain medaka (Oryzias latipes).
abstract: Androgen disrupting chemicals (ADCs) are widespread in the aquatic environment, where they may pose a risk to aquatic organisms during critical periods of development. In this study, static renewal 96-h toxicity tests were followed over a 3-month growth period to investigate the endocrine disrupting effects of the androgen 11-ketotestosterone (11-KT), and the antiandrogen flutamide (FLU) on 1-week-old Qurt strain medaka larvae. The measured endpoints included: survival, growth performance (i.e., body weight, body length, condition index), and histopathology. There was no significant acute mortality, except for males treated with the highest FLU concentration (96 h-LC(50)=1.92 mg/l). Gender-specific effects in growth were identified after 11-KT and FLU treatments. Histopathological alterations including thyroid follicular hypertrophy (TFH), germ cell necrosis (GCN), ovarian atresia (OA), and testis-ova (TO) were observed in medaka at 90-day post-exposure. We observed TFH in all 11-KT treatment levels. The incidence of TFH in males was double that in females 11-KT or FLU treatment. Females showed GCN at lower 11-KT concentrations (0.01, 0.1mg/l) than males (1.0mg/l). Severe OA was observed at low (0.01 mg/l) and high (1.0mg/l) 11-KT concentrations in females. Flutamide induced TO (0.32, 1.0mg/l), ovarian cell necrosis (0.32 mg/l), and disrupted spermatogenesis (3.2mg/l) in males. The lowest observed effective concentration (LOEC) for TO induction in Qurt medaka males was 0.32 mg/l. The present study underscores the importance of fish early life stage tests for detecting the interaction of ADCs with the reproductive and thyroid glands in both genders.
authors: Aquatic Toxicology Program, School of Veterinary Medicine, Department of Anatomy, Physiology, and Cell Biology, 1321 Haring Hall, One Shields Avenue, University of California, Davis, CA 95616, USA.
authors: Abimael
authors: A
authors: León
authors: Swee J
authors: SJ
authors: Teh
authors: Linda C
authors: LC
authors: Hall
authors: Foo C
authors: FC
authors: Teh
mesh_terms: D000726:Androgen Antagonists / Q000633:toxicity*; D000818:Animals; D004703:Endocrine System / Q000187:drug effects; D005260:Female; D005485:Flutamide / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D008297:Male; D009990:Oryzias / Q000502:physiology*; D010053:Ovary / Q000187:drug effects; D012737:Sex Factors; D016019:Survival Analysis; D013737:Testis / Q000187:drug effects; D013739:Testosterone / Q000031:analogs & derivatives* / Q000633:toxicity; D013961:Thyroid Gland / Q000187:drug effects; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000726:Androgen Antagonists; D014874:Water Pollutants, Chemical; D014867:Water; D013739:Testosterone; D005485:Flutamide; C003600:11-ketotestosterone