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Clues from wildlife to create an assay for thyroid system disruption
1Wildlife and Contaminants Program, World Wildlife Fund, 1250 24th Street NW, Washington, DC 20037-9736, USA. colborn@wwfus.org
Environmental Health Perspectives
|June 13, 2002
Summary
This review highlights the critical role of thyroid hormones (THs) in wildlife development and behavior. It examines how environmental contaminants can disrupt TH function, leading to adverse health effects beyond reproductive issues.
Area of Science:
- Environmental toxicology
- Endocrinology
- Wildlife biology
Background:
- U.S. Congress mandated EPA to screen chemicals for endocrine disruption in 1996.
- International efforts focus on estrogenicity, androgenicity, and steroidogenesis, neglecting thyroid disruption.
- Wildlife studies since the 1960s report thyroid abnormalities linked to contaminants.
Purpose of the Study:
- Review literature on thyroid hormones (THs) in wildlife.
- Examine the association between environmental contaminants and thyroid system disruption.
- Provide a basis for developing screening assays for thyroid system agonists and antagonists.
Main Methods:
- Literature review of scientific studies.
- Analysis of research on thyroid gland function, TH concentrations, and behavior in wildlife.
- Examination of studies linking contaminant exposure to thyroid system alterations.
Main Results:
- Few studies have linked environmental contaminants to specific health endpoints beyond reproductive success.
- Thyroid hormone disruption is implicated in abnormal thyroid development and altered TH/retinoid ratios in wildlife.
- Contaminant exposure is associated with changes in the thyroid gland, TH levels, and behavior.
Conclusions:
- Thyroid hormone disruption is an understudied area of endocrine disruption.
- Environmental contaminants can interfere with crucial thyroid hormone functions in wildlife.
- Further research is needed to develop effective screening tools for thyroid system disruptors.