Question

One of the following is NOT a thyroid hormone. It is ______________.

• A. thyrocalcitonin
• B. tyrosine
• C. triiodothyronine
• D. tetraiodothyronine

Hint:

T$_3$ and T$_4$ are iodine-containing derivatives of tyrosine.

Answer 1

The Correct Option is B

Step 1: Understanding thyroid hormones.
The thyroid gland secretes thyroxine (T$_4$), triiodothyronine (T$_3$), and thyrocalcitonin.
Step 2: Nature of tyrosine.
Tyrosine is an amino acid and serves as a precursor for thyroid hormone synthesis.
Step 3: Differentiation.
Although tyrosine is required to form thyroid hormones, it is not itself a hormone.
Step 4: Conclusion.
Hence, tyrosine is not a thyroid hormone.