Terms

Question 1

Iodide Trapping

Answer 1

active process that occurs at the basolateral membrane of thyroid follicular cells via a membrane transport protein (Na-I symporter)

Question 2

Iodide Organification

Answer 2

Iodide oxidation followed by iodination of tyrosine residues of thyroglobulin, mediated by thyroid peroxidase (with help of hydrogen peroxide)

Question 3

Coupling of Residues

Answer 3

done via thyroid peroxidase. monoiodotyrosine (MIT) and diiodotyrosine (DIT):
MIT + DIT = T3: Triiodothyronine
DIT+DIT= T4 Thyroxine

Question 4

Thyroid Peroxidase (PTO)

Answer 4

an enzyme that spans the apical membrane and performs the organification and coupling steps of thyroid hormone synthesis

Question 5

Thyroglobulin

Answer 5

glycoprotein synthesized by the thyroid follicular cells and the enters the colloid through exocytosis. Thyroid hormones are synthesized on Tg as soon as it passes through the apical membrane to enter the colloid for storage

Question 6

5’- deiodinase (D1, D2)

Answer 6

(deiodination) converts T4 to T3; this accounts for 80% of T3 formation

Question 7

5-deiodinase (D3)

Answer 7

converts T4 to reverse T3 or rT3 (inactive)

Question 8

galatorrhea

Answer 8

lactation not associated with pregnancy

caused by excess prolactin

Question 9

5- alpha reductase

Answer 9

converts Testosterone to DHT

Question 10

aromatase

Answer 10

converts testosterone to estradiol