Document Detail

Seasonal changes in critical enzymes of lipogenesis and triacylglycerol synthesis in the marmot (Marmota flaviventris).
MedLine Citation:
PMID:  8300920     Owner:  NLM     Status:  MEDLINE    
Fatty acid metabolism and triacylglycerol synthesis are critical processes for the survival of hibernating mammals that undergo a prolonged fasting period. Fatty acid synthase, fatty-acid-CoA ligase, diacylglycerol acyltransferase, and monoacylglycerol acyltransferase activities were measured in liver and in white and brown adipose tissue, in order to determine whether enzymes of lipogenesis and triacylglycerol synthesis vary seasonally during hibernation in the yellow-bellied marmot (Marmota flaviventris). Compared with mid-winter hibernation, fatty acid synthase activity was higher in all three tissues during early spring when marmots emerged from hibernation and in mid-summer when they were feeding, consistent with the synthesis of fatty acids from the carbohydrate-rich summer diet. Fatty-acid-CoA ligase and diacylglycerol acyltransferase activities were highest in summer in white adipose tissue when triacylglycerol synthesis would be expected to be high; diacylglycerol acyltransferase activity was also high in brown adipose tissue during spring and summer. In liver, however, diacylglycerol acyltransferase specific activity was highest during hibernation, suggesting that triacylglycerol synthesis may be prominent in liver in winter. Monoacylglycerol acyltransferase activity, which may aid in the retention of essential fatty-acids, was 80-fold higher in liver than in white or brown adipose tissue, but did not vary seasonally. Its dependence on palmitoyl-CoA suggests that a divalent cation might play a role in enzyme activation. The high hepatic diacylglycerol acyltransferase activity during hibernation suggests that the metabolism of very low density lipoprotein may be important in the movement of adipose fatty acids to brown adipose tissue and muscle during the rewarming that occurs periodically during hibernation.(ABSTRACT TRUNCATED AT 250 WORDS)
N Mostafa; D C Everett; S C Chou; P A Kong; G L Florant; R A Coleman
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology     Volume:  163     ISSN:  0174-1578     ISO Abbreviation:  J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.     Publication Date:  1993  
Date Detail:
Created Date:  1994-03-07     Completed Date:  1994-03-07     Revised Date:  2009-06-08    
Medline Journal Info:
Nlm Unique ID:  8413200     Medline TA:  J Comp Physiol B     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  463-9     Citation Subset:  IM    
Department of Nutrition, University of North Carolina at Chapel Hill 27599.
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MeSH Terms
Acyltransferases / metabolism
Adipose Tissue / enzymology*
Coenzyme A Ligases / metabolism
Fatty Acid Synthetase Complex / metabolism
Hibernation / physiology*
Liver / enzymology*,  metabolism
Marmota / metabolism*
Repressor Proteins*
Saccharomyces cerevisiae Proteins*
Triglycerides / biosynthesis*
Grant Support
Reg. No./Substance:
0/Repressor Proteins; 0/Saccharomyces cerevisiae Proteins; 0/Triglycerides; EC 2.3.-/Acyltransferases; EC 6.-/Fatty Acid Synthetase Complex; EC 6.2.1.-/Coenzyme A Ligases; EC protein, S cerevisiae; EC ligase

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

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