1,721,011 research outputs found
Il gas naturale nel condizionamento - La valutazione economica delle pompe di calore ad azionamento termico
No full textIl gas naturale nel condizionamento - La valutazione economica delle pompe di calore ad azionamento termico
No full textHedgehog-mediated regulation of thyroid hormone action through iodothyronine deiodinases
No full textThe three iodothyronine deiodinases catalyze the metabolic pathway that removes one iodine residue from the T4 molecule, thus producing either the active T3 or the inactive metabolite rT3. Hence, deiodination is a potent mechanism by which to modulate thyroid hormone (TH) action at cellular level, thereby allowing cells to customize their own T3 availability, both spatially and temporally, irrespective of TH serum concentrations. Sonic hedgehog (Hh) regulates patterning and growth of a remarkable variety of tissues throughout embryogenesis. Its constitutive activation is associated with cancer development
Studio di fattibilità e convenienza economica della cogenerazione al servizio degli impianti di climatizzazione
No full textMetabolic Effects of the Intracellular Regulation of Thyroid Hormone: Old Players, New Concepts
Full text linkThyroid hormones (THs) are key determinants of cellular metabolism and regulate a variety of pathways that are involved in the metabolism of carbohydrates, lipids and proteins in several target tissues. Notably, hyperthyroidism induces a hyper-metabolic state characterized by increased resting energy expenditure, reduced cholesterol levels, increased lipolysis and gluconeogenesis followed by weight loss, whereas hypothyroidism induces a hypo-metabolic state characterized by reduced energy expenditure, increased cholesterol levels, reduced lipolysis and gluconeogenesis followed by weight gain. Thyroid hormone is also a key regulator of mitochondria respiration and biogenesis. Besides mirroring systemic TH concentrations, the intracellular availability of TH is potently regulated in target cells by a mechanism of activation/inactivation catalyzed by three seleno-proteins: type 1 and type 2 iodothyronine deiodinase (D1 and D2) that convert the biologically inactive precursor thyroxine T4 into T3, and type 3 iodothyronine deiodinase (D3) that inactivates TH action. Thus, the pleiotropic effects of TH can fluctuate among tissues and strictly depend on the cell-autonomous action of the deiodinases. Here we review the mechanisms of TH action that mediate metabolic regulation. This review traces the critical impact of peripheral regulation of TH by the deiodinases on the pathways that regulate energy metabolism and the balance among energy intake, expenditure and storage in specific target tissues
Deiodinases and their intricate role in thyroid hormone homeostasis
Full text linkThe deiodinase family of enzymes mediates the activation and inactivation of thyroid hormone. The role of these enzymes in the regulation of the systemic concentrations of thyroid hormone is well established and underpins the treatment of common thyroid diseases. Interest in this field has increased in the past 10 years as the deiodinases became implicated in tissue development and homeostasis, as well as in the pathogenesis of a wide range of human diseases. Three deiodinases have been identified, namely, types 1, 2 and 3 iodothyronine deiodinases, which differ in their catalytic properties and tissue distribution. Notably, the expression of these enzymes changes during the lifetime of an individual in relation to the different needs of each organ and to ageing. The systemic homeostatic role of deiodinases clearly emerges during changes in serum concentrations of thyroid hormone, as seen in patients with thyroid dysfunction. By contrast, the role of deiodinases at the tissue level allows thyroid hormone signalling to be finely tuned within a given cell in a precise time-space window without perturbing serum concentrations of thyroid hormone. This Review maps the overall functional role of the deiodinases and explores challenges and novel opportunities arising from the expanding knowledge of these 'master' components of the thyroid homeostatic system
APPLICAZIONI DI ENERGETICA - INTRODUZIONE ALL'ANALISI TECNICO-ECONOMICA DI SISTEMI DI RISPARMIO ENERGETICO
No full textThe key roles of thyroid hormone in mitochondrial regulation, at interface of human health and disease
Full text link: Mitochondria are highly plastic and dynamic organelles long known as the powerhouse of cellular bioenergetics, but also endowed with a critical role in stress responses and homeostasis maintenance, supporting and integrating activities across multifaced cellular processes. As a such, mitochondria dysfunctions are leading causes of a wide range of diseases and pathologies. Thyroid hormones (THs) are endocrine regulators of cellular metabolism, regulating intracellular nutrients fueling of sugars, amino acids and fatty acids. For instance, THs regulate the balance between the anabolism and catabolism of all the macro-molecules, influencing energy homeostasis during different nutritional conditions. Noteworthy, not only most of the TH-dependent metabolic modulations act via the mitochondria, but also THs have been proved to regulate the mitochondrial biosynthesis, dynamics and function. The significance of such an interplay is different in the context of specific tissues and strongly impacts on cellular homeostasis. Thus, a comprehensive understanding of THs-dependent mitochondrial functions and dynamics is required to develop more precise strategies for targeting mitochondrial function. Herein, we describe the mechanisms of TH-dependent metabolic regulation with a focus on mitochondrial action, in different tissue contexts, thus providing new insights for targeted modulation of mitochondrial dynamics
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