What is the Origin of T3 T4 Hormones?

These hormones are central to the field of endocrinology, with their discovery and structural elucidation being foundational to understanding metabolic control. The numerical designation refers to the number of iodine atoms attached to the thyronine backbone: four for Thyroxine (T4) and three for Triiodothyronine (T3). Clinical practice revolves around measuring and optimizing the circulating levels of both free and total fractions of these molecules.

What is the Mechanism of T3 T4 Hormones?

The thyroid gland synthesizes T4 and a small amount of T3, which are then transported in the blood, largely bound to carrier proteins. T4 is converted into the active T3 in peripheral tissues by deiodinase enzymes, which remove an iodine atom. T3 then enters the cell nucleus and binds to its receptor, acting as a transcription factor to modulate the expression of genes responsible for mitochondrial function and energy expenditure throughout the body.

T3 T4 Hormones

Meaning

T3 and T4 hormones, specifically Triiodothyronine and Thyroxine, are the primary hormones secreted by the thyroid gland, essential for regulating the body’s basal metabolic rate, protein synthesis, and sensitivity to other hormones. T4 is the prohormone, produced in greater quantity, while T3 is the more biologically active form that directly engages cellular receptors. The precise balance and conversion of these hormones are critical determinants of energy, temperature, and neurocognitive function.