Iodine Metabolism

Question 1

T/F Iodine is abundant in the sea

Answer 1

True

Question 2

What is cretinism?

Answer 2

congenital severe stunted growth caused by maternal iodine deficiency

Question 3

What is the function of Betadine?

Answer 3

Betadine contains iodine and is a good antiseptic

Question 4

How much iodine do we need per day?

Answer 4

150 ug

Question 5

What is the action of goitrogen?

Answer 5

inhibit the uptake of iodide

Question 6

which compound in broccoli can act as a goitrogen?

Answer 6

vitamin riboflavin

Question 7

Which channel takes up circulating iodide in the thyroid?

Answer 7

iodide is uptaken via Na/I- exchanger

Question 8

How does the Na/I channel open?

Answer 8

TSH binding to TSH receptor, driving cAMP pathway to open the gate

Question 9

What is the gradient/energy of Na/I- exchange generated by?

Answer 9

Na/K ATPase

Question 10

How does iodide get transported into the colloid?

Answer 10

via Pendrin

Question 11

Which enzyme converts iodide to iodine?

Answer 11

thyroperoxidase

Question 12

How does iodine go on to form T3 and T4

Answer 12

bind to tyrosine on thyroglobulin, forming MIT or DIT, and further reaction to form T3 and T4

Question 13

Where can we find thyroperoxidase?

Answer 13

embedded on the thyroid cell membrane (colloid side)

Question 14

How does T3 and T4 enter the bloodstream

Answer 14

thyroglobulin is first endocytosed into the thyroid cell. T3 and T4 are released into the bloodstream after protease action, while MIT and DIT react with deiodinase to recycle the iodide

Question 15

Which carrier proteins carry free T3 and T4

Answer 15

TBG, albumin, and transthyretin