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.
Original language | English (US) |
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Pages (from-to) | 2663-2668 |
Number of pages | 6 |
Journal | Environmental Toxicology and Chemistry |
Volume | 21 |
Issue number | 12 |
State | Published - Dec 1 2002 |
Keywords
- Endocrine disruptor
- Estrogen bioassay
- Oviduct
- Phytoestrogen
- Taeniopygia guttata
ASJC Scopus subject areas
- Environmental Science(all)
- Environmental Chemistry
- Toxicology
- Health, Toxicology and Mutagenesis