Document Detail

Modulation of glycogen synthesis in rat skeletal muscle by changes in cell volume.
MedLine Citation:
PMID:  8887744     Owner:  NLM     Status:  MEDLINE    
1. The hypothesis that cellular hydration state modulates muscle glycogen synthesis was tested by measuring the incorporation of [14C]glucose into glycogen (glycogen synthesis) in primary rat myotubes after experimentally induced volume changes. 2. Glycogen synthesis in myotubes increased (by 75%, P < 0.01) after swelling induced by 60 min exposure to hyposmotic media (170 mosmol kg-1) relative to isosmotic control (300 mosmol kg-1) values, it decreased (by 31%, P < 0.05) after shrinkage induced by 60 min exposure to hyperosmotic (430 mosmol kg-1) media. Myotube 2-deoxy-D-glucose (0.05 mM) uptake was unaffected by changes in external osmolality. 3. Wortmannin (100 nM; 60 min), a phosphatidylinositol 3-kinase inhibitor, decreased basal glycogen synthesis by 28% whereas rapamycin (100 nM; 60 min), which blocks the activation of p70 S6 kinase, had no effect. Both wortmannin (100 nM; 60 min) and rapamycin (100 nM; 60 min) blocked the changes in glycogen synthesis resulting from hypo- and hyperosmotic exposure. 4. Myotube glycogen synthesis is modulated by volume changes independently of changes in glucose uptake. The phenomenon may be physiologically important in promoting glycogen storage during circumstances of myofibrillar swelling, e.g. after feeding or exercise.
S Y Low; M J Rennie; P M Taylor
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  495 ( Pt 2)     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1996 Sep 
Date Detail:
Created Date:  1997-02-20     Completed Date:  1997-02-20     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  299-303     Citation Subset:  IM    
Department of Anatomy & Physiology, University of Dundee, UK.
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MeSH Terms
Animals, Newborn
Antibiotics, Antineoplastic / pharmacology
Antimetabolites / metabolism
Cell Size / physiology
Cells, Cultured
Culture Techniques
Deoxyglucose / metabolism
Enzyme Inhibitors / pharmacology
Glucose / metabolism
Glycogen / biosynthesis*
Insulin / physiology
Microtubules / physiology,  ultrastructure
Muscle, Skeletal / cytology,  metabolism*,  ultrastructure*
Osmolar Concentration
Polyenes / pharmacology
Signal Transduction / physiology
Reg. No./Substance:
0/Antibiotics, Antineoplastic; 0/Antimetabolites; 0/Enzyme Inhibitors; 0/Polyenes; 11061-68-0/Insulin; 154-17-6/Deoxyglucose; 50-99-7/Glucose; 53123-88-9/Sirolimus; 9005-79-2/Glycogen

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