Endocrine Abstracts

Thyroid hormone (TH) plays an essential role in the proper development of the brain and peripheral tissues. Lack of sufficient TH results in abnormal development, including mental retardation. TH transporters are necessary for the intracellular availability of TH to have access to the deiodinases and nuclear receptors inside the cell. Different specific TH transporters are known to date including the monocarboxylate transporters 8 (MCT8) and 10 (MCT10), and the organic anion t...

Abundant evidence indicates that the three deiodinases (D1, D2 and D3) function at the pre-receptor level to influence both extracellular and intracellular thyroid hormone levels and hence thyroid hormone action. Indirect evidence supports the concept that a major function of the D1 is to generate T3 for export to plasma whereas the D2 generates T3 primarily for local use. To obtain direct evidence concerning their individual physiological roles we have g...

Cardiac contractility, electrophysiology and energy metabolism are markedly dependent on the level of circulating thyroid hormone. Some of the effects are secondary to changes in heart rate and systemic blood pressure, but most genes involved in the effects on cardiac function are transcriptionally regulated by T3. Knock-out models in which expression of the various T3-receptors (TR) was manipulated indicate a principal role of TRα, although signalli...

Thyroid hormone (TH) is long known for its profound effects on metabolism. Novel studies have revealed that these effects are not restricted to the cellular and organ level, and that TH also affects metabolism by altering the autonomic nervous system via TH receptor α1. Mice expressing a mutant R384C TH receptor α1 display a central sympathetic hyperactivation of their brown adipose tissue, which causes severe hypermetabolism and resistance to high-fat diet-induced o...