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[RC] CHO/recovery - Ridecamp Guest

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Authors H Pilegaard, T Osada, LT Andersen, JW Helge, B Saltin, PD Neufer
Title   Substrate availability and transcriptional regulation of metabolic 
genes in human skeletal muscle during recovery from exercise
Full source     Metabolism - Clinical and Experimental, 2005, Vol 54, Iss 8, pp 
1048-1055

In skeletal muscle of humans, transcription of several metabolic genes is 
transiently induced during recovery from exercise when no food is consumed. To 
determine the potential influence of substrate availability on the 
transcriptional regulation of metabolic genes during recovery from exercise, 9 
male subjects (aged 22-27) completed 75 minutes of cycling exercise at 75% 
(V)over dotO(2)max on 2 occasions, consuming either a high-carbohydrate (HC) or 
low-carbohydrate (LC) diet during the subsequent 24 hours of recovery. Nuclei 
were isolated and tissue frozen from vastus lateralis muscle biopsies obtained 
before exercise and 2, 5, 8, and 24 hours after exercise. Muscle glycogen was 
restored to near resting levels within 5 hours in the HC trial, but remained 
depressed through 24 hours in the LC trial. During the 2- to 8-hour recovery 
period, leg glucose uptake was 5- to 15-fold higher with HC ingestion, whereas 
arterial plasma free fatty acid levels were similar to 3- to 7-fold higher with 
LC ingestion. Exercise increased (P<.05) transcription and/or mRNA content of 
the pyruvate dehydrogenase kinase 4, uncoupling protein 3, lipoprotein lipase, 
carnitine palmitoyltransferase I, hexokinase II, peroxisome proliferator 
activated receptor gamma coactivator-1 alpha, and peroxisome proliferator 
activated receptor a. Providing HC during recovery reversed the activation of 
pyruvate dehydrogenase kinase 4, uncoupling protein 3, lipoprotein lipase, and 
carnitine palmitoyltransferase I within 5 to 8 hours after exercise, whereas 
providing LC during recovery elicited a sustained/enhanced increase in 
activation of these genes through 8 to 24 hours of recovery. These findings 
provide evidence that factors associated with substrate availability and/or 
cellular metabolic recovery (eg, muscle glycogen restoration) influence the 
transcriptional regulation of metabolic genes in skeletal muscle of humans 
during recovery from exercise.


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