EIAgen FreeT3

analyte

Free T3

brief description

Triiodothyronine (3, 5, 3' triiodothyronine) or T3 is a thyroid hormone with a molecular weight of 651. In contrast to T4, which is exclusively a product of the thyroid gland, T3 is mainly produced in peripheral tissues by the 5-mono-deiodination of T4. In normal subjects about 80% of T3 produced by peripheral conversion, and about 20% is secreted by the thyroid. Evidence suggests that T3 is the most important thyroid hormone, and some authors contend that T4 may have no intrinsic activity and serves merely as a prohormone for T3. Circulating levels of T3 can be influenced by changes in thyroid gland function or by alteration in the peripheral metabolism of T4. In serum, T3 exists in a reversible equilibrium between two states, bound and free. T3 bound to serum binding proteins, primarily thyroxine binding globulin (TBG) and to a lesser degree albumin and prealbumin, represents greater than 99 % of the total T3.

intended use

The EIAgen Free T3 is an EIA method for the quantitative determination of free triiodothyronine (fT3) in human serum.