Thyroid, Seals, EDC Paper Flashcards
What was tested in the harbour seal paper?
The relationship between contaminants and specific thyroid hormone receptor gene expression in harbour seals.
What are the 4 main biological characteristics of persistent organic pollutants?
- Lipophilic ring structure can mimic thyroid/steroid hormone
- Long half-life
- Bioaccumulate
- Disrupt endocrine systems
What was the main finding of the harbour seal paper?
When seals were exposed to more pollutants, their level of thyroid receptor alpha increased and thyroxine decreased.
Why use harbour seals as a study model?
They don’t migrate, are abundant, have homology with humans, and have previously been used for similar studies.
What were the 3 main objectives of the harbour seal study?
- Develop biomarkers for TR gene expression
- Confirm ability to use TR expression as marker for pollutant exposure
- Test feasibility of using TR expression to study harbour seals
From which 5 sites were samples taken during the harbour seal study?
- Queen Charlotte Strait
- Hornby Island
- Vancouver
- Smith Island (near Vancouver, but good flow)
- Gertrude Island (basically Seattle)
What kind of result is considered a “statistically significant” finding?
One with a p value less than 0.05 (<5/100 chance of being random)
What kind of result is considered a “statistically highly significant” finding?
One with a p value less than 0.001 (<1/1000 chance of being random)
What did the main figures show in the harbour seal paper?
Thyroxine (TT4) levels decreased as pollutant levels increased. Expression of thyroid receptors increased as pollutant levels increased.
What are the 2 biggest takeaways from the findings of the harbour seal study?
- Thyroid produces less hormone when pollutant levels are high
- Receptors are overexpressed in response to elevated thyroid hormone-like molecules
