Biomarkers

Target: Liothyronine

Liothyronine which is also known as Triiodothyronine or T3 is a thyroid hormone. Liothyronine is the manufactured form of T3. Triiodothyronine is a thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. Triiodothyronine or T3 is one of two major hormones derived from the thyroid gland, the other being thyroxine (T4). The major form of thyroid hormone in the blood is thyroxine (T4), which has a longer half-life than T3. In humans, the ratio of T4 to T3 released into the blood is approximately 14:1. T4 is converted to the active T3 (three to four times more potent than T4) within cells by deiodinases (5′-iodinase). Thyroid hormones function via a well-studied set of nuclear receptors, termed the thyroid hormone receptors. They act on nearly every cell in the body. In particular, thyroid hormones act to increase the basal metabolic rate, affect protein synthesis, help regulate long bone growth (synergy with growth hormone) and neural maturation, and increase the body's sensitivity to catecholamines (such as adrenaline) by permissiveness. The thyroid hormones are essential to proper development and differentiation of all cells of the human body. These hormones also regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds. They also stimulate vitamin metabolism. Numerous physiological and pathological stimuli influence thyroid hormone synthesis.