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High fat feeding inhibits exercise induced increase in mitochondrial respiratory flux in skeletal muscle.
MedLine Citation:
PMID:  21415171     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Twenty one healthy untrained male subjects were randomized to follow a high fat diet (HFD) (55-60E% fat, 25-30E% carbohydrate and 15E% protein) or a normal diet (ND) (25-35E% fat, 55-60E% carbohydrate and 10-15E% protein) for 2 1/2 wk. Diets were isocaloric and tailored individually to match energy expenditure. At 2 1/2 wk of diet one 60 min bout of bicycle exercise (70% of maximal oxygen uptake) was performed. Muscle biopsies were obtained before and after the diet, and immediately after exercise and after 3 hrs recovery. Insulin sensitivity (hyperinsulinemic euglycemic clamp), and intramyocellular triacylglycerol content did not change with the intervention in either group. Indices of mitochondrial density were similar across the groups and intervention. Mitochondrial respiratory rates, measured in permeabilized muscle fibers, showed a 31 ± 11% and 26 ± 9% exercise induced increase (P<0.05) in state 3 (glycolytic substrates) and uncoupled respiration, respectively. However, in HFD this increase was abolished. At recovery no change from resting respiration was seen in either group. With a lipid substrate (octanoyl-carnitine +/- ADP), similar exercise induced increases (31-62%) were seen in HFD and ND, but only in HFD was an elevated (P<0.05) respiratory rate seen at recovery. With HFD complex I and IV protein expression decreased (P<0.05 and P=0.06, respectively). Conclusion: A fat rich diet induces marked changes in the mitochondrial electron transport system protein content and in exercise induced mitochondrial substrate oxidation rates, with the effects being present hours after the exercise. The effect of HFD is present even without effects on insulin sensitivity and intramyocellular lipid accumulation. An isocaloric high fat diet does not cause insulin resistance.
Authors:
Mette Skovbro; Robert Boushel; Christina Neigaard Hansen; Jorn Wulff Helge; Flemming Dela
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-3-17
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  -     ISSN:  1522-1601     ISO Abbreviation:  -     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-3-18     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
1University of Copenhagen.
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