Abstract
The thyroid hormone (TH) is essential for the development of various tissues and exerts a direct influence on the metabolism of all vertebrates. Secreted in the form of T4, which is considered the forerunner molecule is converted to T3, which is the physiologically active form of thyroid hormone. The deiodinases type 1, 2 and 3 are important for the regulation of the amount of T3 in tissu…