Document Detail


Fuel selection in Wistar rats exposed to cold: shivering thermogenesis diverts fatty acids from re-esterification to oxidation.
MedLine Citation:
PMID:  19622609     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study characterizes the effects of shivering thermogenesis on metabolic fuel selection in Wistar rats. Because lipids account for most of the heat produced, we have investigated: (1) whether the rate of appearance of non-esterified fatty acids (R(a) NEFAs) is stimulated by shivering, (2) whether mono-unsaturated (oleate) and saturated fatty acids (palmitate) are affected similarly, and (3) whether the partitioning between fatty acid oxidation and re-esterification is altered by cold exposure. Fuel oxidation was measured by indirect calorimetry and fatty acid mobilization by continuous infusion of 9,10-[(3)H]oleate and 1-[(14)C]palmitate. During steady-state cold exposure, results show that total heat production is unequally shared by the oxidation of lipids (52% of metabolic rate), carbohydrates (35%) and proteins (13%), and that the same fuel selection pattern is observed at all shivering intensities. All previous research shows that mammals stimulate R(a) NEFA to support exercise or shivering. In contrast, results reveal that the R(a) NEFA of the rat remains constant during cold exposure (55 micromol kg(1) min(1)). No preferential use of mono-unsaturated over saturated fatty acids could be demonstrated. The rat decreases its rate of fatty acid re-esterification from 48.4 +/- 6.4 to 19.6 +/- 6.3 micromol kg(1) min(1) to provide energy to shivering muscles. This study is the first to show that mammals do not only increase fatty acid availability for oxidation by stimulating R(a) NEFA. Reallocation of fatty acids from re-esterification to oxidation is a novel, alternative strategy used by the rat to support shivering.
Authors:
Eric Vaillancourt; François Haman; Jean-Michel Weber
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-07-21
Journal Detail:
Title:  The Journal of physiology     Volume:  587     ISSN:  1469-7793     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2009 Sep 
Date Detail:
Created Date:  2009-09-01     Completed Date:  2009-12-14     Revised Date:  2013-06-02    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  4349-59     Citation Subset:  IM    
Affiliation:
University of Ottawa, Department of Biology, 30 Marie-Curie, PO Box 450, Station A, Ottawa, Ontario, Canada K1N 6N5. ericvaillancourt@uottawa.ca
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MeSH Terms
Descriptor/Qualifier:
Acclimatization / physiology
Animals
Choice Behavior / physiology
Cold Temperature
Eating / physiology*
Esterification
Fatty Acids / metabolism*
Feeding Behavior / physiology*
Heat-Shock Response / physiology*
Male
Oxidation-Reduction
Rats
Rats, Wistar
Shivering / physiology*
Chemical
Reg. No./Substance:
0/Fatty Acids
Comments/Corrections

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


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