תזונה ותוספים Protein Intake Does Not Increase Vastus Lateralis Muscle Protein Synthesis during Cyc

[Mike Bikov]

Med Sci Sports Exerc. 2011 Feb 28. [Epub ahead of print]
Protein Intake Does Not Increase Vastus Lateralis Muscle Protein Synthesis during Cycling.

Hulston CJ, Wolsk E, Grøndahl TS, Yfanti C, Hall GV.

1Metabolic Mass-Spectrometry Facility, 2Copenhagen Muscle Research Centre, 3Centre of Inflammation and Metabolism, Rigshospitalet, Copenhagen, Denmark. 4Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark.
Abstract

PURPOSE: To investigate the effect of protein ingestion on leg protein turnover and vastus lateralis muscle protein synthesis during bicycle exercise and recovery.

METHODS: Eight healthy males participated in two experiments in which they ingested either a carbohydrate solution (CHO) providing 0.49 g/kg/h or a carbohydrate and protein solution (CHO+P) providing 0.49 g/kg/h and 0.16 g/kg/h during 3 h bicycle exercise and 3 h recovery. Leg protein turnover was determined from stable isotope infusion (L-[ring-C6]phenylalanine), femoral-arterial venous blood sampling and blood flow measurements. Muscle protein synthesis was calculated from the incorporation of L-[ring-C6]phenylalanine into protein.

RESULTS: Consuming protein during exercise increased leg protein synthesis and decreased net leg protein breakdown; however, protein ingestion did not increase protein synthesis within the highly active vastus lateralis muscle (0.029 ± 0.004 and 0.030 ± 0.003 %/h in CHO and CHO+P, respectively; P = 0.88). In contrast, consuming protein, during exercise and recovery, increased post-exercise vastus lateralis muscle protein synthesis by 51 ± 22 % (0.070 ± 0.003 and 0.105 ± 0.013 %/h in CHO and CHO+P, respectively; P < 0.01). Furthermore, leg protein net balance was negative during recovery with CHO intake whereas positive leg protein net balance was achieved with CHO+P intake.

CONCLUSION: We conclude that consuming protein during prolonged bicycle exercise does not increase protein synthesis within highly active leg muscles. However, protein intake may have stimulated protein synthesis within less active leg muscles and/or other nonmuscle leg tissue. Finally, protein supplementation, during exercise and recovery, enhanced post-exercise muscle protein synthesis and resulted in positive leg protein net balance.

PMID: 21364482 [PubMed - as supplied by publisher]

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