Document Detail

Muscle protein synthesis and gene expression during recovery from aerobic exercise in the fasted and fed states.
MedLine Citation:
PMID:  20720176     Owner:  NLM     Status:  MEDLINE    
The purpose of this investigation was to assess mixed-muscle fractional synthesis rate (FSR) and the expression of genes involved in skeletal muscle remodeling after aerobic exercise in the fasted and fed states. Eight recreationally active males (25 ± 1 yr; Vo(2 max): 52 ± 2 ml·kg(-1)·min(-1)) performed 60-min of cycle ergometry at 72 ± 1% Vo(2 max) on two occasions in a counter-balanced design. Subjects ingested a noncaloric placebo (EX-FAST) or a beverage containing (per kg body wt): 5 kcal, 0.83 g carbohydrate, 0.37 g protein, and 0.03 g fat (EX-FED) immediately and 1 h after exercise. FSR was assessed at rest and following exercise with the use of a l-[ring (2)H(5)]-phenylalanine infusion combined with muscle biopsies at 2 and 6 h postexercise. mRNA expression was assessed at 2 and 6 h postexercise via real-time RT-PCR. FSR was higher (P < 0.05) after exercise in both EX-FAST (0.112 ± 0.010%·h(-1)) and EX-FED (0.129 ± 0.014%·h(-1)) compared with rest (0.071 ± 0.005%·h(-1)). Feeding attenuated the mRNA expression (P < 0.05) of proteolytic factors MuRF-1 (6 h) and calpain-2 (2 and 6 h) postexercise but did not alter FOXO3A, calpain-1, caspase3, or myostatin mRNA expression compared with EX-FAST. Myogenic regulatory factor (MRF4) mRNA was also attenuated (P < 0.05) at 2 and 6 h postexercise in EX-FED compared with EX-FAST. These data demonstrate that a nonexhaustive bout of aerobic exercise stimulates skeletal muscle FSR in the fasted state and that feeding does not measurably enhance FSR between 2 and 6 h after aerobic exercise. Additionally, postexercise nutrient intake attenuates the expression of factors involved in the ubiquitin-proteosome and Ca(2+)-dependent protein degradation pathways. These data provide insight into the role of feeding on muscle protein metabolism during recovery from aerobic exercise.
Matthew P Harber; Adam R Konopka; Bozena Jemiolo; Scott W Trappe; Todd A Trappe; Paul T Reidy
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Publication Detail:
Type:  Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-08-18
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  299     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-03     Completed Date:  2010-12-01     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1254-62     Citation Subset:  IM    
Human Performance Laboratory, Ball State Univ., Muncie, IN 47306, USA.
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MeSH Terms
Blood Glucose / metabolism
Dietary Carbohydrates / administration & dosage
Dietary Fats / administration & dosage
Dietary Proteins / administration & dosage
Fatty Acids / blood
Gene Expression Regulation
Glycogen / metabolism
Infusions, Intravenous
Insulin / blood
Muscle Contraction*
Muscle Proteins / biosynthesis*,  genetics
Muscle, Skeletal / metabolism*
Oxygen Consumption
Phenylalanine / administration & dosage,  analogs & derivatives
RNA, Messenger / metabolism
Recovery of Function
Time Factors
Young Adult
Reg. No./Substance:
0/Blood Glucose; 0/Dietary Carbohydrates; 0/Dietary Fats; 0/Dietary Proteins; 0/Fatty Acids; 0/Muscle Proteins; 0/RNA, Messenger; 11061-68-0/Insulin; 63-91-2/Phenylalanine; 9005-79-2/Glycogen

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

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