Thyroid and Antithyroid Drugs Flashcards
What is D3? Where is it expressed? What is it’s function?
Type 3 (D3) deiodinase:
Predominantly expressed in the brain and skin in healthy adults. Also expressed in placenta of pregnant women and also other tissues in disease states (i.e. tumors).
Function: Inactivates T3; converts T3 into T2 (3’,5’-T2) and reverse T3 (rT3: 3,3’,5’-T3).
Is thought to have tissue-specific effects; preventing circulating T3 from entering the nucleus.
How does iodine get into the tyroid follicular epithelial cells (single cell layer surrounding colloid!)?
Sodium iodine cor-transporter driven by sodium gradient generated by constitutively active Na/K-ATPase
***Hashimoto’s autoantibody is raised against the sodium iodiine co-transporter ==> consequence is impairment of iodine uptake and hypothyroidism!!
**Congentital abnormalties in co-transport also lead to hypothyroidism
