nbme1 neonate thyroid problem seems easy but - quansar

[ArchivalUser]

1. a neonate with swelling of the neck has a decreased T4 and increased TSH. Which of the following agents chronically ingested by the mother during the pregnancy is the most likely cause

a) corticosteroids
b) propranolol
c) propylthiouracil
d) T4
e) T3

[ArchivalUser]

c.

[ArchivalUser]

shoudn't propylthiouracil inhibit conversion T4 to T3, so that T3 should decrease instead of T4

and?

maybe propylthiouracil has other functions

[ArchivalUser]

only high dose propylthiuracil inhibit T4 to T3 conversion, while the general dose can inhibit organificatio by peroxidase, iodination of tyrosyl residues and coupling reactions.

[ArchivalUser]

azaaza, so for normal use of propylthiouracil, which one is decreased more? T4 or T3? and how does that relate to TSH level?

[ArchivalUser]

Hi, quansar,
1. I don't see the meaning to compare the degree of normal use of propylthiuracil's effect on T4 and T3.
2. although T4 is rsponsible for most of the negative feedbak, T3 also can have feedback.
that is my understanding

[ArchivalUser]

well wat is the answer guys.....just imagine if she takes a drug which is gonna pass thro the placenta and cause hypothryroidsim in this kid...wat cud it be...or say the drug which wud cause hyperplasia of the throid with out increasing in T4.....corticosteroids...well any one agrees...