| Responsiveness to thyroid hormone and to ambient temperature underlies differences between brown adipose tissue and skeletal muscle thermogenesis in a mouse model of diet-induced obesity. | |
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MedLine Citation:
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PMID: 21771890 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Thyroid hormone accelerates energy expenditure (EE) and is critical for cold-induced thermogenesis. To define the metabolic role played by thyroid hormone in the dissipation of calories from diet, hypothyroid mice were studied for 60 d in a comprehensive lab animal monitoring system. Hypothyroidism decreased caloric intake and body fat while down-regulating genes in the skeletal muscle but not brown adipose tissue thermogenic programs, without affecting daily EE. Only at thermoneutrality (30 C) did hypothyroid mice exhibit slower rate of EE, indicating a metabolic response to hypothyroidism that depends on ambient temperature. A byproduct of this mechanism is that at room temperature (22 C), hypothyroid mice are protected against diet-induced obesity, i.e. only at thermoneutrality did hypothyroid mice become obese when placed on a high-fat diet (HFD). This is in contrast to euthyroid controls, which on a HFD gained more body weight and fat at any temperature while activating the brown adipose tissue and accelerating daily EE but not the skeletal muscle thermogenic program. In the liver of euthyroid controls, HFD caused an approximately 5-fold increase in triglyceride content and expression of key metabolic genes, whereas acclimatization to 30 C cut triglyceride content by half and normalized gene expression. However, in hypothyroid mice, HFD-induced changes in liver persisted at 30 C, resulting in marked liver steatosis. Acclimatization to thermoneutrality dramatically improves glucose homeostasis, but this was not affected by hypothyroidism. In conclusion, hypothyroid mice are metabolically sensitive to environmental temperature, constituting a mechanism that defines resistance to diet-induced obesity and hepatic lipid metabolism. |
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Authors:
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Cintia B Ueta; Emerson L Olivares; Antonio C Bianco |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2011-07-19 |
Journal Detail:
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Title: Endocrinology Volume: 152 ISSN: 1945-7170 ISO Abbreviation: Endocrinology Publication Date: 2011 Sep |
Date Detail:
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Created Date: 2011-08-24 Completed Date: 2011-10-31 Revised Date: 2012-01-05 |
Medline Journal Info:
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Nlm Unique ID: 0375040 Medline TA: Endocrinology Country: United States |
Other Details:
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Languages: eng Pagination: 3571-81 Citation Subset: AIM; IM |
Affiliation:
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Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, Florida 33136, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adipose Tissue, Brown
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metabolism*,
physiopathology Animals Body Composition Diet Energy Metabolism Hypothyroidism / metabolism*, physiopathology Male Mice Muscle, Skeletal / metabolism*, physiopathology Obesity / etiology, metabolism*, physiopathology Temperature Thermogenesis / physiology* |
| Comments/Corrections | |
Erratum In:
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Endocrinology. 2011 Dec;152(12):5079 |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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