Document Detail

Resynthesis of glycogen in skeletal muscle from standardbred trotters after repeated bouts of exercise.
MedLine Citation:
PMID:  9028482     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To determine glycogen resynthesis rate and changes in plasma metabolite concentrations in horses before and after repeated exercise. ANIMALS: 6 clinically normal Standardbred trotters. PROCEDURE: Horses trotted distances of 3,000, 3,000, and 2,000 m (trial A) and 3 days later, trotted 2,100, 2,100, and 1,600 m (trial B). Horses had 1 hour rest periods between bouts of exercise. Trotting speed was increased with each exercise bout, up to a near maximal. Muscle biopsy specimens and venous blood samples were obtained before each trial and 0, 4, 24, 48, and 72 hours after the third bout. Blood samples were also taken between exercise bouts. Muscle glycogen content and plasma glucose, glycerol, nonesterified fatty acid, and triglyceride concentrations were determined. RESULTS: Muscle glycogen content was significantly decreased immediately after exercise from 473 +/- 45 to 329 +/- 79 mmol/kg of dry weight in trial A, and from 472 +/- 128 to 347 +/- 59 mmol/kg in trial B. Further decreases were measured 4 hours after exercise. Glycogen resynthesis was negligible 24 hours after exercise. Basal muscle concentrations of glycogen were obtained 72 hours after exercise in trial A (472 +/- 128 mmol/kg), but not in trial B (279 +/- 52 mmol/kg). Plasma concentrations of glucose were greater than or equal to before-exercise values. Plasma concentrations of lipid metabolites, glycerol, triglycerides, and nonesterified fatty acids, were less than before-exercise values 2 to 72 hours after exercising. CONCLUSIONS: Repeated bouts of exercise decrease glycogen repletion rate, which is not attributable to hypoglycemia, but may be influenced by limited availability of lipids for energy production.
S Hyyppä; L A Räsänen; A R Pösö
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  American journal of veterinary research     Volume:  58     ISSN:  0002-9645     ISO Abbreviation:  Am. J. Vet. Res.     Publication Date:  1997 Feb 
Date Detail:
Created Date:  1997-06-03     Completed Date:  1997-06-03     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0375011     Medline TA:  Am J Vet Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  162-6     Citation Subset:  IM; S    
Agricultural Research Centre, Ypäjä. Hyyppä.
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MeSH Terms
Analysis of Variance
Blood Glucose / metabolism*
Fatty Acids, Nonesterified / blood*
Glycogen / biosynthesis*
Horses / physiology*
Muscle, Skeletal / metabolism*
Physical Conditioning, Animal*
Physical Exertion*
Time Factors
Triglycerides / blood*
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Triglycerides; 9005-79-2/Glycogen

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

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