Читать книгу The Healthy Thyroid: What you can do to prevent and alleviate thyroid imbalance - Patsy Westcott - Страница 18

The thyroid’s main purpose is the production, storage and release of thyroid hormone. Although referred as a single entity, there are, in fact, two thyroid hormones: thyroxine (T₄) and triiodothyronine (T₃), which carry four and three atoms of iodine, respectively.

T₃ is four times more potent than T₄ and works eight times more quickly. Yet, T₄ is about 50 times more abundant in the bloodstream than T₃. This is because, although small amounts of T₄ are converted to T₃ within the thyroid gland itself, most T₃ is produced outside of the thyroid by a process called monodeiodination, which strips away one of the iodine atoms from T₄. This allows the body to produce T₃ as needed – like changing your five-pound notes into one-pound coins for the parking meter.