Endocrine Abstracts

Thyroid hormone plays a critical role in the production and maintenance of myelin, the lipid-rich sheath that surrounds the outer surface of axons. Myelin is made from processes that extend from oligodendrocytes (OL), a glia cell that comprises about 20% of the cells in the adult central nervous system (CNS). Mature, myelinating OL are produced from a differentiation pathway that begins with neural stem cells and involves the differentiation of oligodendrocyte progenitor cells...

We have recently discovered a novel, endogenous iodine containing aryl-ethylamine derivative that we believe is a metabolite of thyroxine, the major form of thyroid hormone produced in the thyroid gland of vertebrates. This compound is 3-iodothyronamine (T1AM), and it does not bind to or activate nuclear thyroid hormone receptors – the established target receptors of thyroid hormones – but instead functions as a potent agonist of trace amine associated receptor 1 (TA...

In 2004, we reported the discovery of a new signaling molecule chemically related to thyroid hormones called 3-iodothyronamine (T1AM). T1AM is formally a decarboxylated and deiodinated derivative of thyroxine (T4) and was detected in tissues and circulation of rodents. Single-dose administration of T1AM to mice resulted in unique biological activities including hypothermia, bradycardia, and hyperglycemia. The T1AM-induced ...

Iodothyronamines are endogenous trace amines which are putative products of thyroid hormone decarboxylation by Aromatic Amino acid Decarboxylase (AADC). 3-Iodothyronamine (T1AM) has been shown to have profound effects on rodents in vivo, including reductions in body temperature, blood pressure and cardiac output, alongside a switch from carbohydrate to fat utilisation. It is possible that T1AM induces some of these effec...

3-iodothyronamine (3-T1AM) and thyronamine (T0AM) are novel endogenous signaling molecules that exhibit great structural similarity to thyroid hormones but apparently antagonize classical thyroid hormone (T3) actions. Their proposed biosynthesis from thyroid hormones would require decarboxylation and more or less extensive deiodination. Deiodinases (Dio1, Dio2 and Dio3) catalyze the removal of iodine from their substrates. Since a role of deiod...

Inactivating mutations in the thyroid hormones (TH) transporter monocarboxylate transporter 8 (MCT8) lead to the X-linked rare disease named MCT8 deficiency or Allan-Herndon-Dudley Syndrome (AHDS). AHDS pathophysiology is characterized by peripheral hyperthyroidism and cerebral hypothyroidism, which results in severe neurological impairments. Although AHDS leads to a spectrum of severe endocrine and neurological alterations, treatment options for MCT8-deficient patients are li...

3-Iodothyronamine (T1AM) is a novel endogenous derivative of thyroid hormone (TH), recently described by Scanlan et al. (Nat. Med. 10: 638, 2004). In vitro, T1AM can stimulate the production of cAMP via activation of a heterologously expressed G protein-coupled receptor (GPCR) now referred to as trace amine-associated receptor 1 (TAAR1; Lindemann et al. Genomics 85: 372, 2005). In adult, unanesthetized C57Bl6/J mice, T1AM produces prof...