Document Detail


Hepatic overexpression of a constitutively active form of liver glycogen synthase improves glucose homeostasis.
MedLine Citation:
PMID:  20841354     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In this study, we tested the efficacy of increasing liver glycogen synthase to improve blood glucose homeostasis. The overexpression of wild-type liver glycogen synthase in rats had no effect on blood glucose homeostasis in either the fed or the fasted state. In contrast, the expression of a constitutively active mutant form of the enzyme caused a significant lowering of blood glucose in the former but not the latter state. Moreover, it markedly enhanced the clearance of blood glucose when fasted rats were challenged with a glucose load. Hepatic glycogen stores in rats overexpressing the activated mutant form of liver glycogen synthase were enhanced in the fed state and in response to an oral glucose load but showed a net decline during fasting. In order to test whether these effects were maintained during long term activation of liver glycogen synthase, we generated liver-specific transgenic mice expressing the constitutively active LGS form. These mice also showed an enhanced capacity to store glycogen in the fed state and an improved glucose tolerance when challenged with a glucose load. Thus, we conclude that the activation of liver glycogen synthase improves glucose tolerance in the fed state without compromising glycogenolysis in the postabsorptive state. On the basis of these findings, we propose that the activation of liver glycogen synthase may provide a potential strategy for improvement of glucose tolerance in the postprandial state.
Authors:
Susana Ros; Delia Zafra; Jordi Valles-Ortega; Mar García-Rocha; Stephen Forrow; Jorge Domínguez; Joaquim Calbó; Joan J Guinovart
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-09-14
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  285     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-24     Completed Date:  2010-12-30     Revised Date:  2011-12-21    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  37170-7     Citation Subset:  IM    
Affiliation:
Department of Biochemistry and Molecular Biology, Institute for Research in Biomedicine, University of Barcelona, Baldiri Reixac 10, E-08028 Barcelona, Spain.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Glucose*
Gene Expression*
Glycogen Synthase / genetics*,  metabolism*
Liver / enzymology,  metabolism*
Liver Glycogen / metabolism*
Male
Mice
Mice, Inbred C57BL
Mice, Transgenic
Rats
Rats, Transgenic
Rats, Wistar
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Liver Glycogen; EC 2.4.1.11/Glycogen Synthase

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


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