Question

The immediate precursor of thyroxine is
A) Tyrosine
B) Tryptophane
C) Pyridoxine
D) Thymidine

Answer 1

Hint: We have different glands in different part of the body that produce different hormones. These hormones are involved in the regulation and maintenance of different body functions.

Complete Answer:
- Hormones are called the chemical messengers as they secreted directly in the circulatory system. With the help of blood the hormones are reached to the organs and the tissue to maintain their function.
- There are many types of hormones that are secreted in the body to maintain the processes and function. Thyroxine and triiodothyronine are the two hormones secreted by thyroid glands, insulin, estrogen, progesterone, cortisol, etc.
- Now, the immediate precursor of thyroxine is tyrosine. Thyroxine is the hormone secreted by the thyroid gland and is made from iodine and tyrosine.
- The thyrotropin-releasing hormone formed by the hypothalamus stimulates the formation of thyroid stimulating hormone in the anterior portion of the pituitary gland. This TSH then stimulates the receptor of the thyroid stimulating hormone, Iodine is added to the 3’ and 5’ area of tyrosine and the regular iodination steps results in the production of T3 and T4 hormone.

Thus, the correct answer is ‘A’. Tyrosine.

Note: The catecholamine is a precursor of epinephrine and norepinephrine that releases inside the circulatory system when a person is having some emotional stress. The norepinephrine, epinephrine, and dopamine are the main catecholamines.