MSI_000024427

3,5-Diiodothyronine, also known as 3,5-T2, belongs to the class of organic compounds known as phenylalanines and derivatives. Phenylalanine and derivatives are compounds containing phenylalanine or a derivative thereof resulting from reaction of phenylalanine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. It is also a member of the class of compounds known as iodothyronines. Iodothyronines are phenolic amino acids with iodine substituents. 3,5-Diiodothyronine is a metabolite of the two main thyroid hormones T3 and T4 (thyroxine and triiodo-L-thyronine). It is a biologically active iodothyronine with mitochondria and bioenergetic mechanisms being the major targets of 3,5-T2. Nanomolar concentrations of 3,5-T2 significantly increases cytochrome oxidase (COX) activity (PMID: 30090086). It increases COX activity by preventing the interaction of adenosine triphosphate (ATP) as an allosteric inhibitor. At 1 pM concentration, 3,5-T2 stimulates oxygen consumption more rapidly than thyroxine (T3). A case report involving two human participants revealed that administration of 3,5-T2 to humans (1–5 ug/kg BW) rapidly (after 4–6 h) increased resting metabolic rate. Chronic 3,5-T2 administration (28 days, approximately 5 ug/kg BW) increased resting metabolic rate by approximately 15\\% and decreased body weight by approximately 4 kg in both participants (PMID: 22217997). 3,5-T2 stimulates the thyroid receptor (TR)-beta receptor for thyroid hormones and thus increases energy expenditure. It has agonistic (thyromimetic) effects on myocardial tissue and on the pituitary, which results in 3,5-T2 suppressing thyroid stimulating hormone release. 3,5-Diiodothyronine is a metabolite of thyroid hormones (thyroxine and triiodo-L-thyronine). It has specific actions and those actions do not involve thyroid hormone receptors. (PMID 15807655) [HMDB] D006730 - Hormones, Hormone Substitutes, and Hormone Antagonists > D006728 - Hormones