Thyroxine

**Semantic type:** Amino Acid, Peptide, or Protein|Hormone

**Definition:** A hormone synthesized and secreted by the thyroid gland containing four iodine atoms and is converted to triiodothyronine (T3) in the body, influencing metabolism and organ function.

**Synonyms:** - L-3,5,5'-tetraiodothyronine - T4 - T4 - thyroxin - thyroxine