Document Detail

Muscle and liver glycogen content: diurnal variation and endurance.
MedLine Citation:
PMID:  572822     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to determine the influence of diurnal variations of muscle and liver glycogen stores on exercise endurance in male albino rats. Animals were swum to exhaustion at either 0700 or 1900 h, after which samples of soleus, white vastus lateralis, and red vastus lateralis muscles as well as liver were excised and subsequently analyzed for glycogen content. Glycogen content of all tissues from nonexercising control animals was higher in the morning than in the evening. Consequently, animals at 0700 h swam 60% longer than those at 1900 h (209 +/- 20 min vs. 130 +/- 23 min, respectively). However, because the skeletal tissues of the exhausted animals were not totally depleted of glycogen, it was concluded that fatigue under the swim protocol was the result of hypoglycemia secondary to hepatic glycogen depletion. The results of this study demonstrate the physiological consequences of diurnal glycogen fluctuation and establish experimental support for the importance of controlling this variable in rodent exercise investigations.
J H Clark; R K Conlee
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology: respiratory, environmental and exercise physiology     Volume:  47     ISSN:  0161-7567     ISO Abbreviation:  J Appl Physiol Respir Environ Exerc Physiol     Publication Date:  1979 Aug 
Date Detail:
Created Date:  1979-10-24     Completed Date:  1979-10-24     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  7801242     Medline TA:  J Appl Physiol Respir Environ Exerc Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  425-8     Citation Subset:  IM; S    
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MeSH Terms
Circadian Rhythm*
Glycogen / metabolism*
Liver / metabolism*
Muscles / metabolism*
Physical Endurance*
Physical Exertion
Reg. No./Substance:

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