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
