Trijódtironina

Trijódtironina, also known as T3, is a thyroid hormone that plays a crucial role in regulating metabolism in vertebrates. It is synthesized in the thyroid gland and is one of the two major hormones produced by this gland, the other being thyroxine (T4). T3 is the more potent form of thyroid hormone, meaning it has a stronger effect on target cells and tissues.

The synthesis of Trijódtironina involves the iodination of tyrosine residues, followed by coupling of these iodinated tyrosines. T3 is primarily formed from the deiodination of T4 in peripheral tissues, although a smaller amount is directly secreted by the thyroid gland. The thyroid gland produces T4 in larger quantities, which then circulates in the bloodstream and is converted to the more active T3 as needed by various organs.

Trijódtironina binds to nuclear receptors within cells, influencing gene expression and thereby affecting a wide range of physiological processes. These include regulating basal metabolic rate, body temperature, heart rate, growth and development, and the breakdown of carbohydrates, fats, and proteins. Its presence is essential for normal development, particularly in the brain and skeletal system during fetal life and childhood.

Disruptions in Trijódtironina levels can lead to various thyroid disorders. Hyperthyroidism, characterized by excessive T3 and T4 production, can result in symptoms such as weight loss, rapid heartbeat, and anxiety. Hypothyroidism, conversely, involves insufficient thyroid hormone production, leading to fatigue, weight gain, and cold intolerance. The measurement of Trijódtironina levels in blood tests is a common diagnostic tool for assessing thyroid function.