Document Detail


Effects of exercise on muscle glycogen synthesis signalling and enzyme activities in pigs carrying the PRKAG3 mutation.
MedLine Citation:
PMID:  20028849     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The dominant RN mutation in pigs results in excessive glycogen storage in skeletal muscle. The mutation is situated in the PRKAG3 gene, which encodes a muscle-specific isoform of the AMP-activated protein kinase (AMPK) gamma3 subunit. AMPK is an important regulator of carbohydrate and fat metabolism in mammalian cells. The aim of the present study was to examine the effect of exercise on glycogen synthesis signalling pathways in muscle and to study enzyme activities of importance in carbohydrate metabolism in pigs with or without the PRKAG3 mutation. Glycogen content, metabolic enzyme activities and expression or phosphorylation of signalling proteins were analysed in skeletal muscle specimens obtained at rest, after a single treadmill exercise bout and after 3 h recovery. The PRKAG3 mutation carriers had higher glycogen content, a tendency for lower expression of AMPK (P < 0.07) and higher hexokinase and phosphorylase activities, whereas citrate synthase, 3-hydroxyacyl-CoA dehydrogenase and glycogen synthase activities did not differ between genotypes. Carriers and non-carriers of the RN mutation showed a similar degradation of glycogen after exercise, whereas the rate of resynthesis was faster in the carriers. Acute exercise stimulated Akt phosphorylation on Ser(473) in both genotypes, and the effect was greater in the carriers than in the non-carriers. Acute exercise also stimulated phosphorylation of Akt substrate of 160 kDA and Glycogen synthase kinase 3 in the carriers and GSK3alpha in the non-carriers. In conclusion, the increased rate of glycogen synthesis following exercise in pigs carrying the PRKAG3 mutation correlates with an increased signalling response of Akt and its substrate, AS160, and a higher activity of hexokinase, indicating an increased glucose influx and phosphorylation of glucose, directed towards glycogen synthesis.
Authors:
Anna Granlund; Olga Kotova; Boubacar Benziane; Dana Galuska; Marianne Jensen-Waern; Alexander V Chibalin; Birgitta Essén-Gustavsson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-12-22
Journal Detail:
Title:  Experimental physiology     Volume:  95     ISSN:  1469-445X     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-03-17     Completed Date:  2010-06-07     Revised Date:  2012-06-19    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  541-9     Citation Subset:  IM    
Affiliation:
Department of Clinical Sciences, Section for Comparative Physiology and Medicine, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden. anna.granlund@kv.slu.se
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MeSH Terms
Descriptor/Qualifier:
AMP-Activated Protein Kinases / genetics*
Animals
GTPase-Activating Proteins / metabolism
Glycogen / biosynthesis*,  metabolism
Glycogen Synthase Kinase 3 / metabolism
Hexokinase / metabolism
Muscle, Skeletal / metabolism
Phosphorylation
Physical Conditioning, Animal / physiology*
Proto-Oncogene Proteins c-akt / metabolism
Swine
Chemical
Reg. No./Substance:
0/GTPase-Activating Proteins; 9005-79-2/Glycogen; EC 2.7.1.1/Hexokinase; EC 2.7.11.1/AMP-Activated Protein Kinases; EC 2.7.11.1/Proto-Oncogene Proteins c-akt; EC 2.7.11.1/glycogen synthase kinase 3 beta; EC 2.7.11.26/Glycogen Synthase Kinase 3; EC 2.7.11.26/glycogen synthase kinase 3 alpha

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


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