Thyroxine (thyroid hormone) production (Homo sapiens)

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Thyroxine hormone is produced in the thyroid gland from tyrosine and iodine. Thyrotropin-releasing hormone (TRH) is produced by the hypothalamus. It stimulates the production of thyroid-stimulating hormone (TSH) in the anterior pituitary gland, which affects the thyroid-stimulating hormone receptor (TSHR). Iodine is captured by a hydrogen peroxide trap procuced by thyroid peroxidase and added to the 3' and 5' postitions of tyrosine. This can either be free tyrosine or a tyrosine residue in thyroglobuline. After the multiple iodination steps this produces T3 and T4. The production of the thyroid hormones thyroxine (T4),tri-iodothyronine (T3) and reverse T3 (rT3) is dependent on the organification ofiodine into thyroglobulin (Tg), the major protein product of the thyroid (2). This involves thyroid peroxidase catalyzed iodination of tyrosine residues in Tg to form mono- and di-iodotyrosines and their subsequent crosslinking to form the iodothyronines T3 and T4.

• Homo sapiens
• Metabolic Process