If the thyroid gland is unable to produce iodinated thyroglobulin, what is the effect on hormone production?

Question: If the thyroid gland is unable to produce iodinated thyroglobulin, what is the effect on hormone production?

Triiodothyronine (T3) and thyroxine (T4) production continues uninterrupted.

Excess triiodothyronine (T3) and thyroxine (T4) hormones are made.

Less thyroid-stimulating hormone (TSH) is made.

Less triiodothyronine (T3) and thyroxine (T4) hormones are made.

Answer:

Less triiodothyronine (T3) and thyroxine (T4) hormones are made.

Explanation:

The follicular cells of the thyroid glands actively absorb iodide ions from the blood. Inside the follicular cells, a large glycoprotein called thyroglobulin is also formed. The thyroglobulin has some amino acids including tyrosine in it. The oxidation of iodide ions in the follicular cells forms the iodine atoms which in turn react with tyrosines of thyroglobulin molecules. Binding of two iodine atom to tyrosine obtains diiodotyrosine (T2). Then, two T2 molecules join to form T4, or one T1 and one T2 join to form T3.

In this way, the iodination of tyrosine of thyroglobulin forms T3 and T4 hormones. If the gland is not able to produce thyroglobulin, T3 and T4 hormone synthesis will be reduced.