Document Detail

Regulation of porcine skeletal muscle nuclear 3,5,3'-tri-iodothyronine receptor binding capacity by thyroid hormones: modification by energy balance.
MedLine Citation:
PMID:  7706977     Owner:  NLM     Status:  MEDLINE    
Thyroid hormones have been implicated in the regulation of nuclear 3,5,3'-tri-iodothyronine (T3) receptor binding capacity (Bmax) but, despite numerous in vivo and in vitro studies, there is considerable controversy regarding their exact role. Since changes in thyroid status alter energy balance and hence may influence T3 receptor numbers, the effects of chronic hypothyroidism and T4 treatment have been studied in young pigs under conditions of controlled energy intake. Four groups of animals comprising a hypothyroid, a euthyroid and a hyperthyroid group, all on the same level of food intake, and a hyperthyroid group on twice the amount of food were used. After 3 weeks on the treatment regimes, both the hypothyroid animals on the same level of food intake and the hyperthyroid animals on twice the amount of food had significantly increased Bmax values (97% and 137% higher respectively) compared with euthyroid controls. However, there was no difference between controls and the hyperthyroid animals on the same level of food intake. In a second study, the effects of short-term treatment of euthyroid animals with T3 was investigated. Results showed that in two groups of controls that received intravenous saline, those on a higher food intake had higher Bmax values (76% increase). Intravenous T3 administration to animals on a low food intake did not change the receptor numbers. In none of the studies was there any change in the dissociation constant of the receptors as a result of different treatments. It is suggested that, at least in postnatal life, thyroid hormones per se have no significant effect on nuclear T3 receptor numbers in skeletal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
A Morovat; M J Dauncey
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of endocrinology     Volume:  144     ISSN:  0022-0795     ISO Abbreviation:  J. Endocrinol.     Publication Date:  1995 Feb 
Date Detail:
Created Date:  1995-05-10     Completed Date:  1995-05-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375363     Medline TA:  J Endocrinol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  233-42     Citation Subset:  IM    
Department of Cellular Physiology, Babraham Institute, Cambridge, UK.
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MeSH Terms
Binding Sites
Cell Nucleus / metabolism*
Energy Intake / physiology
Energy Metabolism / physiology*
Hypothyroidism / enzymology,  metabolism
Iodide Peroxidase / metabolism
Liver / enzymology
Muscle, Skeletal / metabolism*
Protein Binding
Receptors, Thyroid Hormone / metabolism*
Thyroxine / pharmacology
Triiodothyronine / blood,  metabolism*
Reg. No./Substance:
0/Receptors, Thyroid Hormone; 6893-02-3/Triiodothyronine; 7488-70-2/Thyroxine; EC Peroxidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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