Final answer:
The thyroid gland uses iodine to produce the hormones thyroxine and triiodothyronine, which are critical for metabolism and require iodine for their synthesis.
Step-by-step explanation:
The gland that uses iodine to produce hormones is the thyroid gland. This gland is located in the neck and comprises two lobes. The hormones produced by the thyroid are thyroxine (T4) and triiodothyronine (T3), both of which require iodine for their synthesis.
Insufficient iodine intake can lead to conditions such as goiter and cretinism. The thyroid also plays a role in regulating the body's metabolic rate, among other functions. The islets of Langerhans in the pancreas also play an important role in endocrine function by regulating blood sugar levels through the secretion of hormones such as insulin and glucagon.