Levothyroxine Lactose Adduct is a derivative of Thyroxine (T425600), which is one of the thyroid hormones involved in the maintenance of metabolic homeostasis. Synthesized and stored as amino acid residues of thyroglobulin, the major protein component of the thyroid follicular colloid. Synthesis and secretion are regulated by the pituitary hormone (TSH). Deiodinated in peripheral tissues to the active metabolite, liothyronine. The D-form has very little activity as a thyroid hormone, but has been used to treat hyperlipidemia. Molecular Formula: C27H31I4NO14 Molecular Weight: 1101.1500000000001