1.
Thyroid Hormones, Metabolic Syndrome and Its Components.
Delitala, AP, Fanciulli, G, Pes, GM, Maioli, M, Delitala, G
Endocrine, metabolic & immune disorders drug targets. 2017;(1):56-62
Abstract
Metabolic syndrome is a clustering of various metabolic parameters, which include diabetes, low high-density lipoprotein cholesterol, elevated triglycerides, abdominal obesity, and hypertension. It has merged as a worldwide epidemic and a major public health care concern. However, due to the different criteria used for the assessment, the frequency of metabolic syndrome in the general population is variable but it is more common in the older people. Metabolic syndrome is closely linked to cardiovascular risk and increases cardiovascular outcomes and all-cause mortality. Recent evidences showed that alterations of the thyroid function could have an impact on the components of the metabolic syndrome, suggesting that thyroid hormones have a variety of effects on energy homeostasis, lipid and glucose metabolism, and blood pressure. In this review, we summarize available data on the action of thyroid hormone on the components of metabolic syndrome.
2.
Disorder of thyroid hormone transport into the tissues.
Groeneweg, S, Visser, WE, Visser, TJ
Best practice & research. Clinical endocrinology & metabolism. 2017;(2):241-253
Abstract
Transport of thyroid hormone (TH) across the plasma membrane is essential for intracellular TH metabolism and action, and this is mediated by specific transporter proteins. During the last two decades several transporters capable of transporting TH have been identified, including monocarboxylate transporter 8 (MCT8), MCT10 and organic anion transporting polypeptide 1C1 (OATP1C1). In particular MCT8 and OATP1C1 are important for the regulation of local TH activity in the brain and thus for brain development. MCT8 is a protein containing 12 transmembrane domains, and is encoded by the SLC16A2 gene located on the X chromosome. It facilitates both TH uptake and efflux across the cell membrane. Male subjects with hemizygous mutations in MCT8 are afflicted with severe intellectual and motor disability, also known as the Allan-Herndon-Dudley syndrome (AHDS), which goes together with low serum T4 and high T3 levels. This review concerns molecular and clinical aspects of MCT8 function.
3.
Thyroid hormone transporters and resistance.
Visser, TJ
Endocrine development. 2013;:1-10
Abstract
Cellular entry is an important step preceding intracellular metabolism and action of thyroid hormone (TH). Transport of TH across the plasma membrane does not take place by simple diffusion but requires transporter proteins. One of the most effective and specific TH transporters identified to date is monocarboxylate transporter 8 (MCT8), the gene of which is located on the X chromosome. Although MCT8 is expressed in many tissues, its function appears to be most critical in the brain. Hemizygous MCT8 mutations in males cause severe psychomotor retardation, known as the Allan-Herndon-Dudley syndrome (AHDS), and abnormal serum TH levels. AHDS thus represents a type of TH resistance caused by a defect in cellular TH transport.