Tetrajodotyronina

Tetrajodotyronina is the scientific name for thyroxine, commonly known as T4. It is a thyroid hormone produced by the thyroid gland. T4 is one of the two major hormones secreted by the thyroid, the other being triiodothyronine (T3). These hormones are crucial for regulating metabolism in vertebrates. Tetrajodotyronina is synthesized from tyrosine and iodine. The thyroid gland actively takes up iodine from the bloodstream to produce T4 and T3. T4 contains four iodine atoms, hence its name tetrajodotyronina.

Once produced, tetrajodotyronina is released into the bloodstream. While it is released in larger quantities than T3, it is considered a prohormone. This means that most of the T4 circulating in the body is converted into the more active form, T3, in peripheral tissues such as the liver and kidneys. This conversion is carried out by enzymes called deiodinases. Tetrajodotyronina plays a role in regulating heart rate, body temperature, and growth and development, particularly in children. It also influences the breakdown of carbohydrates and fats. The secretion of T4 is regulated by the pituitary gland through thyroid-stimulating hormone (TSH).