Androgen disruption of early development in Qurt strain medaka (Oryzias latipes)

Abimael León, Swee J Teh, Linda C. Hall, Foo C. Teh

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


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-LC50 = 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, 0.1 mg/l) than males (1.0 mg/l). Severe OA was observed at low (0.01 mg/l) and high (1.0 mg/l) 11-KT concentrations in females. Flutamide induced TO (0.32, 1.0 mg/l), ovarian cell necrosis (0.32 mg/l), and disrupted spermatogenesis (3.2 mg/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.

Original languageEnglish (US)
Pages (from-to)195-203
Number of pages9
JournalAquatic Toxicology
Issue number3
StatePublished - May 15 2007
Externally publishedYes


  • Androgens
  • Antiandrogens
  • Endocrine disruption
  • Oryzias latipes
  • Qurt medaka

ASJC Scopus subject areas

  • Aquatic Science


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