An avian bioassay for environmental estrogens: the growth response of zebra finch (Taeniopygia guttata) Chick oviduct to oral estrogens

Research output: Contribution to journalArticle

Authors

  • JR Millam
  • CB Craig-Veit
  • ME Batchelder
  • TM Herbeck
  • LW Woods

Colleges, School and Institutes

Abstract

The rat uterotrophic assay is a recommended tier 1 screening assay for environmental estrogens, but no comparable assay exists for altricial birds. We orally dosed zebra finch chicks daily during their linear growth phase (days 5-11) with estradiol benzoate (EB), genistein, methoxychlor, or octylphenol, all dissolved or suspended in canola oil, or canola oil alone, as a vehicle control. On day 12, oviducts were removed, weighed and examined histologically. All doses of EB (0.1-1,000 nmol/g body wt), genistein at 100 nmol/g. and methoxychlor and octylphenol at 1,000 nmol/g, markedly increased oviduct weight, with the highest dose of EB inducing a 60-fold increase over controls. Oviducts were differentiated in a dose-depedent manner to the point of having tubular glands and a pseudostratified, ciliated epithelium at the higher doses of EB. Our earlier results show that EB at 100 and 1,000 nmol/g impairs reproductive performance of zebra finches. Thus, the zebra finch oviduct bioassay measures estrogenicity over a wide dose range and, for EB exposure, can predict impairment in adult reproductive performance. The responsiveness of chick oviducts to estrogen stimulation may serve as a useful marker of estrogen exposure in wild populations of songbirds.

Details

Original languageEnglish
Pages (from-to)2663-2668
Number of pages6
JournalEnvironmental Toxicology and Chemistry
Volume21
Publication statusPublished - 1 Jan 2002