Document Detail

Endurance training induces muscle-specific changes in mitochondrial function in skinned muscle fibers.
MedLine Citation:
PMID:  12015357     Owner:  NLM     Status:  MEDLINE    
The present study was conducted to investigate the potential role of changes in the apparent K(m) for ADP and in the functional coupling of the creatine (Cr) kinase (CK) system (CK efficiency) in explaining the tighter integration of ATP supply and demand after exercise training. Mitochondrial function was assessed in saponin-skinned fibers from the soleus and the deep red portion of the medial gastrocnemius isolated from trained (T; treadmill running, 5 days/wk, 4 wk) and control (C) female Sprague-Dawley rats. In the soleus, V(max) in the presence of 1 mM ADP was increased by 21% after training (5.9 +/- 0.2 vs. 4.7 +/- 0.4 nmol O(2). min(-1). mg dry wt(-1), P < 0.05). This was accompanied by no change in the K(m) for ADP measured in the absence of Cr (146 +/- 9 vs. 149 +/- 13 microM in T and C, respectively) and in its presence (50 +/- 4 vs. 48 +/- 6 microM in T and C, respectively) and in CK efficiency [K(m) (+Cr)/K(m) (-Cr)]. In contrast, in the red gastrocnemius, training decreased, by 35%, the apparent K(m) for ADP in the absence (83 +/- 5 vs. 129 +/- 9 microM, P < 0.01) of Cr, without affecting V(max) (6.2 +/- 0.4 vs. 6.7 +/- 0.3 nmol O(2). min(-1). mg dry wt(-1) in T and C, respectively) and CK efficiency. These results thus suggest that training induces muscle-specific adaptations of mitochondrial function and that a change in the intrinsic sensitivity of mitochondria to ADP could at least partly explain the tighter integration of ATP and demand commonly observed after training.
Yan Burelle; Peter W Hochachka
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  92     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-05-16     Completed Date:  2002-10-23     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2429-38     Citation Subset:  IM    
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
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MeSH Terms
Adenosine Diphosphate / pharmacology
Creatine / pharmacology
Histological Techniques
Mitochondria, Muscle / physiology*
Muscle Fibers, Fast-Twitch / physiology
Muscle Fibers, Skeletal / physiology*
Muscle Fibers, Slow-Twitch / physiology
Muscle, Skeletal / drug effects,  enzymology,  physiology
Oxygen Consumption / drug effects
Physical Conditioning, Animal*
Physical Endurance* / physiology*
Rats, Sprague-Dawley
Reference Values
Reg. No./Substance:
57-00-1/Creatine; 58-64-0/Adenosine Diphosphate

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

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