Iodine uptake is seen in following organs:
**Core Concept**
Iodine uptake is a critical process for the synthesis of thyroid hormones. The thyroid gland, along with other organs, utilizes iodine to produce thyroid hormones, which are essential for various bodily functions. Iodine uptake involves the transport of iodide ions into cells, where they are oxidized and incorporated into thyroxine (T4) and triiodothyronine (T3).
**Why the Correct Answer is Right**
The correct answer involves organs that express the sodium-iodide symporter (NIS), a transmembrane glycoprotein responsible for the uptake of iodide ions from the bloodstream into thyroid follicular cells and other iodine-accumulating tissues. The NIS is a key protein that enables the thyroid gland to concentrate iodine, which is essential for thyroid hormone synthesis. Other organs, such as the salivary glands, stomach, and lactating mammary glands, also express NIS and take up iodine, albeit to a lesser extent.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the liver and kidneys do not express significant amounts of NIS and therefore do not take up iodine in a manner relevant to thyroid hormone synthesis.
**Option B:** This option is incorrect because the pancreas is not known to express NIS or take up iodine in a significant manner.
**Clinical Pearl / High-Yield Fact**
The sodium-iodide symporter is a critical protein for thyroid hormone synthesis, and its expression is a key factor in the development of thyroid follicular cells and the regulation of iodine uptake.
**Correct Answer:** C.