Thyroid Flashcards
What are the four thyroid hormones?
Thyroxine (tetraiodothyronine)
triiodothyronine
MIT (mono-iodated tyrosine)
DIT
What can be used as a diagnostic tool for TSH release? (hypothyroidism)
Protirelin (Thypinone)–> synthetic TRH
Using TRH as a diagnostic is common. What are three scenarios we would see when we administer it to hypothyroidal patients?
TSH rises but T3 and T4 stay the same –> thyroid problem
TSH does not rise –> pituitary problem
TSH and T3 and T4 rise –> HP problem
What can be used as a diagnostic tool for T3 and T4 release? (hypothyroidism)
Thytropar –> synthetic TSH
How can administering Thytropar test for hypothyroidism?
Adminstering Thytropar results in low iodine absorbtion in the thyroid.
Which enzyme is responsible for converting T4 to T3? Name 2 specific ones
Deiodinase isoenzymes
- D1 and D2
What should you give to patients with hypothyroidism?
T4 and T3
NOT TRH or TSH
Which is more potent, T4 or T3?
T3
What do alpha 2 thyroid receptors bind? Beta receptors?
Alpha 2 - T4 only
Beta - all of them bind T3 and some T4
What is Gull’s Disease?
A severe form of hypothyroidism
What do the first, second and third degrees of hypothyroidism?
1 = iodine deficiency 2 = defective TSH secretion 3 = defective TRH secretion
What is one major side effect of the first degree Gull’s disease? How does this happen?
Infertility –> low T4 –> increased TRH and prolactin –> interferes with LH/FSH
Distinguish the differences between Grave’s disease and Plummer’s disease.
Grave’s –> ophthalmopathy, diffuse goiter, happens at young age
Plummer’s –> no eye stuff, nodular goiter, happens at old age
Why are thioamides not readily used for hyperthyroid patients?
Due to their poisoning effects on the Na/K pump
What is the MOA of thioamides?
Inhibition of iodide conversion to iodine
Inhibition of coupling to iodotyrosine
What is the MOA of proplythiouracil?
Inhibition of T4 to T3 conversion
Whatis the MOA of glucocorticocoids?
Inhibition of T4 to T3 conversion
What is the MOA of high doses of iodide?
Inhibition of iodide conversion to iodine
Inhibition of coupling to iodotyrosine
Inhibits T4/T3 release
