thyroid and antithyroid Flashcards
function of thyroid peroxidase
oxidation and organification of iodide AND coupling of mono-iodotyrosine and diodotyrosine
DIT + DIT - T4
DIT + MIT - T2
thyroid hormone fxn
bone growth and CNS development
enhance B1 receptors in heart = increase CO/HR/SV/contractility
Increase BMR via Na/K ATPase
Increase glycogenolysis, gluconeogenesis, lipolysis
thyroglobulin proteins affected by pregnancy and OCP
TBG increases
action of reverse T3
binds T3 receptors and blocks T3 receptors
unknown pharmalogical fxn
what kind of pathway do TRH, TSH, and T3/T4 use?
TRH = IP3 TSH = cAMP T3/4 = intranuclear receptor binding
control gene expression
what drugs can cause primary hypothyroidism
lithium
amiodarone
levothyroxine
T4
liothyronine
T3
not used too frequently
thyroid preparations MOA
stimulation of nuclear receptors = gene expression with RNA formulation and protein synthesis
thyroid preparation use
hypothyroidism
cretinism
off label as weight loss supplements
thyroid preparation kinetics
T4 –> T3 = T3 is much more potent
any inducers can increase metabolism of thyroid hormones
thyroid prep AE
thyrotoxicosis:
sweating, warm skin, inc appetite, dyspnea, tachycardic, weight loss, menstrual irregularity, infertile, increased deep tendon reflexes
drugs used in hyperthyroidism
1) thioamides
2) iodine/salts
3) 131 Iodide
4) beta blocker
5) diatrizoate, glucocorticoids
propylthiouracil
thioamide
inhibits both TPO and 5-deiodinase = decreases drops in T3 AND T4
reserved for pt who are intolerant to methimazole
used in thyroid storm (b/c dec both T3 and T4)
used in 1st trimester (less teratogen than methimazole)
methimazole
thioamide
inhibits only TPO