Research Area: Endocrinology , Biological Activity: Propylthiouracil is a thyroperoxidase and 5’-deiodinase inhibitor. It is a thioamide drug used to treat hyperthyroidism (including Graves’ disease) by decreasing the amount of thyroid hormone produced by the thyroid gland. It normally acts in thyroid hormone synthesis by oxidizing the anion iodide (I-) to iodine (I0), facilitating iodine’s addition to tyrosine residues on the hormone precursor thyroglobulin. It also acts by inhibiting the enzyme 5’-deiodinase (tetraiodothyronine 5’ deiodinase), which converts T4 to the active form T3. [1] |