Document Detail

Liver glycogenolysis during exercise without a significant increase in cAMP.
MedLine Citation:
PMID:  224717     Owner:  NLM     Status:  MEDLINE    
Liver glycogenolysis may be controlled by glucagon or catecholamine-induced changes in cAMP or by cAMP-independent mechanisms. The purpose of these experiments was to determine whether an increase in liver cAMP occurs during exercise at a time when the rate of liver glycogenolysis is greatly accelerated. Rats were taught to run on a treadmill 10 min/day for 6 wk. They were then run continuously for periods of time ranging from 0 to 120 min at 0.8 mph up a 15% grade. Liver glycogen was depleted by the end of 90 min in fed animals and by 20 min in overnight-fasted animals. Liver cAMP was not significantly increased in fed animals during the first 60 min of exercise. The major increase in liver cAMP occurred after liver glycogen was depleted, at which time the rat must rely entirely on gluconeogenesis for maintenance of blood glucose. This increase in cAMP corresponded to large increases in plasma glucagon and catecholamines. We conclude that liver glycogenolysis in the rat can occur during exercise independently from significant detectable increases in cAMP concentrations.
W W Winder; J Boullier; R D Fell
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  237     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1979 Sep 
Date Detail:
Created Date:  1979-10-26     Completed Date:  1979-10-26     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R147-52     Citation Subset:  IM    
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MeSH Terms
Cyclic AMP / metabolism*
Epinephrine / blood
Glucagon / blood
Insulin / blood
Liver Glycogen / metabolism*
Norepinephrine / blood
Physical Exertion*
Reg. No./Substance:
0/Liver Glycogen; 11061-68-0/Insulin; 51-41-2/Norepinephrine; 51-43-4/Epinephrine; 60-92-4/Cyclic AMP; 9007-92-5/Glucagon

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

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