Biosynthesis of Ta andT3 Dietary iodine(I)ingestion Active transport and uptake of iodide(i) by thyroid gland Oxidation of I and iodination of thyroglobulin(tg) tyrosine residues o Coupling of iodotyrosine residues(mit and dit)to form T and t 3 Proteolysis of Tg with release of T, and t, into the circulationBiosynthesis of T4 and T3  Dietary iodine (I) ingestion  Active transport and uptake of iodide (I- ) by thyroid gland  Oxidation of I- and iodination of thyroglobulin (Tg) tyrosine residues  Coupling of iodotyrosine residues (MIT and DIT) to form T4 and T3  Proteolysis of Tg with release of T4 and T3 into the circulation