PHARM 27 Flashcards
(30 cards)
Concentrates Iodide on basolateral membrane of follicular cells
NIS (na/I symporter)
organification
thyroglobulin iodination –> MIT and DIT
catalyzes t4 –> T3
iodothyronine 5’ deiodinase
Deiodinase that is expressed in liver and kidneys, coverts serum T4
Type I
Deiodinase expressed in pituitary gland, brain, and brown fat converts T4 locally
Type II
Converts T4 - rT3
Type III Deiodinase
Two types of thyroid hormone receptors
alpha and beta
TR react with this to form heterodimers
retinoid X receptor RXR
TSH producing cells
thyrotropes
thryoid stimulating immunoglobulin
IgG autoantibody specific for TSH receptor
L-isomer of T4
levothyroxine
how does increase of hepatic p450 effect thyroid hormone?
it increases excretion
Perchlorate, thiocyanate, pertechnetate are what class of drugs
Inhibitors of iodide uptake – compete for iodide uptake into thyroid gland follicular cell
What radioactive Iodine is used as radiative treatment of hyperthyroidism?
131 I-
What is the Wolff-Chaikoff effect?
high levels of iodide inhibit thyroid hormone synthesis and release
Propylthiouracil and methimazole are what kind of drugs
Thioamines that compete with thyroglobulin for iodide – decrease organification
drugs that cause goiter
goitrogens (thioamines bc no thyroid hormone= TSH stimulation)
Inhibits thyroid peroxidase as well as peripheral T4 –> T3
propylthiouracil
only inhibits thyroid peroxidase and not peripheral T3 conversion
methimazole
Preferred b-antagonist for treatment of thyroid storm
esmolol
5’ deiodinase inhibitor
Ipodate
How does amiodarone cause hypothyroidism?
metabolism releases iodide which concentrates in thyroid gland –> wolff- Chaikoff effect
Type 1 thyrotoxicosis via amiodarone
excess iodide = increase thyroid hormone increase and release
type 2 thyrotoxicosis via amiodarone
autoimmune throiditis induced –> excess thyroid hormone from colloid
