Metabolism ofthyroid hormones 1. Uptake of iodide 2. Activation of iodide(peroxidase), and iodination and coupling of tyrosine 3. Formation of thyroxine(T4) and triiodothyronine (T3)from iodotyrosine Secretion of thyroid hormones(proteolytic enzymes 5. Regulation by thyroid stimulating hormone (TSH), T4, T3