Endocrine Abstracts

The classical genomic actions of triiodothyronine (T3) are mediated by high-affinity nuclear receptors that directly regulate gene expression. By contrast, the non-genomic effects of thyroid hormones occur rapidly and are unaffected by inhibitors of transcription and protein synthesis. The genomic actions of thyroid hormone have an established role in the development, differentiation and homeostatic maintenance of target tissues. The THRA and THRB gene...

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...

Iodothyronines stimulate neovascularization in tumor beds, brain, ischemic myocardium and striated muscle. The molecular basis of the action can be studied in models such as the chick chorioallantoic membrane (CAM) and human microvascular endothelial cell (HDMEC) microtubule formation. Nongenomic and genomic actions of the hormone may contribute to angiogenesis. The initial description of the cell surface receptor for thyroid hormone (T4 and 3,5,3′-triiodo-<sm...

Thyroid hormones exert their effects by stimulation of thyroid hormone receptors that have different tissue distribution and metabolic targets. TRβ is predominant in liver and mainly responsible for effects on cholesterol and lipoprotein metabolism, whereas TRα is most important in fat, muscle and heart. Thyroid hormone analogs (thyromimetics, tiromes) have been developed that activate TRβ are selectively taken up and/or activated by the liver. Such compounds st...