Thyroid Gland Functions and Disease Flashcards
Peripheral conversion of T4 to T3 is done by what enzyme?
Deiodinase
Which deiodinase type is predominantly in the peripheral tissues?
Type 1
During fasting, would you expect more or less conversion of T4 to T3.
Less
What factors are associated with increase in conversion of T4 to T3
Obesity
cold exposure
hyperthyroid
What factors are associated with decrease in conversion of T4 to T3?
Pregnancy fasting beta blockers hepatic and renal failure aging hypothyroid
How many Na comes in with I- in the NIS?
2 Na.
What aa is the precursor for thyroglobulin?
Tyrosine
What what channel does I- go from the cell to the colloid?
Pendrin
Via what transport mechanism do TG-T3-T4 bound complex get inside the cell after TSH stimulation?
Pinocytosis inside a endosome.
NIS can be blocked by what drug?
Percholarate, thiocynate.
PTU is an effective treatment for hyperthyroidsim which works by blockig action of what enzyme?
peroxidase
High levels of I- inhibits organification and synthesis of thyroid hormones. this effect is known as
Walff-Chaikoff
Of the iodide that comes into the thyroid gland is stored in what form?
Stored iodinated as tyrosines of thyroglobulin inside the colloid of follicular lumen.
With iodine deficiency, how long can you go without showing signs of hypothyroidism?
2-3 months
Which thyroid hormone binding protein brings the thyroid hormone to the brain?
Transthyretin.
Thyroxine-binding protein (TBG) has a higher affinity for which thyroid hormone (T3 or T4?
T4