For how long does the thyroxine is stored in the thyroid follicle?
**Core Concept**
Thyroxine (T4) is a hormone produced by the thyroid gland, stored in the thyroid follicles, and released into the bloodstream as needed. The storage and release of T4 are regulated by the hypothalamic-pituitary-thyroid axis.
**Why the Correct Answer is Right**
Thyroxine is stored in the thyroid follicles in the form of thyroglobulin, a protein that binds to iodinated tyrosine residues. The stored thyroglobulin is then broken down into T4 and triiodothyronine (T3) by the enzyme thyroid peroxidase. The stored T4 is released into the bloodstream in response to the release of thyroid-stimulating hormone (TSH) from the anterior pituitary gland. The duration of storage of T4 in the thyroid follicle is approximately **6-8 weeks**.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not provide a specific duration for the storage of T4 in the thyroid follicle.
**Option B:** This option is incorrect because it suggests a much longer duration of storage than is actually the case.
**Option C:** This option is incorrect because it suggests a much shorter duration of storage than is actually the case.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the storage and release of T4 from the thyroid follicle are tightly regulated by the hypothalamic-pituitary-thyroid axis, and any disruption to this axis can lead to thyroid hormone deficiency or excess.
**Correct Answer:** C.