QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Blomstrand, E. Articles by Köhnke, R. Search for Related Content PubMed PubMed Citation Articles by Blomstrand, E. Articles by Köhnke, R.

---

Branched-Chain Amino Acids: Metabolism, Physiological Function, and Application: Session III

Branched-Chain Amino Acids Activate Key Enzymes in Protein Synthesis after Physical Exercise^1–3,

Eva Blomstrand^*,,4, Jörgen Eliasson^*,, Håkan K. R. Karlsson^** and Rickard Köhnke^*

^* Åstrand Laboratory, University College of Physical Education and Sports, Department of Physiology and Pharmacology, and ^** Department of Surgical Science, Karolinska Institutet, Stockholm, Sweden

⁴ To whom correspondence should be addressed. E-mail: eva.blomstrand{at}gih.se.

ABSTRACT

BCAAs (leucine, isoleucine, and valine), particularly leucine, have anabolic effects on protein metabolism by increasing the rate of protein synthesis and decreasing the rate of protein degradation in resting human muscle. Also, during recovery from endurance exercise, BCAAs were found to have anabolic effects in human muscle. These effects are likely to be mediated through changes in signaling pathways controlling protein synthesis. This involves phosphorylation of the mammalian target of rapamycin (mTOR) and sequential activation of 70-kD S6 protein kinase (p70 S6 kinase) and the eukaryotic initiation factor 4E-binding protein 1. Activation of p70 S6 kinase, and subsequent phopsphorylation of the ribosomal protein S6, is associated with enhanced translation of specific mRNAs. When BCAAs were supplied to subjects during and after one session of quadriceps muscle resistance exercise, an increase in mTOR, p70 S6 kinase, and S6 phosphorylation was found in the recovery period after the exercise with no effect of BCAAs on Akt or glycogen synthase kinase 3 (GSK-3) phosphorylation. Exercise without BCAA intake led to a partial phosphorylation of p70 S6 kinase without activating the enzyme, a decrease in Akt phosphorylation, and no change in GSK-3. It has previously been shown that leucine infusion increases p70 S6 kinase phosphorylation in an Akt-independent manner in resting subjects; however, a relation between mTOR and p70 S6 kinase has not been reported previously. The results suggest that BCAAs activate mTOR and p70 S6 kinase in human muscle in the recovery period after exercise and that GSK-3 is not involved in the anabolic action of BCAAs on human muscle.

KEY WORDS: • BCAAs • exercise • protein synthesis • skeletal muscle

This article has been cited by other articles:

				N. A. Burd, J. E. Tang, D. R. Moore, and S. M. Phillips Exercise training and protein metabolism: influences of contraction, protein intake, and sex-based differences J Appl Physiol, May 1, 2009; 106(5): 1692 - 1701. [Abstract] [Full Text] [PDF]

				J. J. Hulmi, J. Tannerstedt, H. Selanne, H. Kainulainen, V. Kovanen, and A. A. Mero Resistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in men J Appl Physiol, May 1, 2009; 106(5): 1720 - 1729. [Abstract] [Full Text] [PDF]

				M. J. Drummond, M. Miyazaki, H. C. Dreyer, B. Pennings, S. Dhanani, E. Volpi, K. A. Esser, and B. B. Rasmussen Expression of growth-related genes in young and older human skeletal muscle following an acute stimulation of protein synthesis J Appl Physiol, April 1, 2009; 106(4): 1403 - 1411. [Abstract] [Full Text] [PDF]

				E. I. Glover, B. R. Oates, J. E. Tang, D. R. Moore, M. A. Tarnopolsky, and S. M. Phillips Resistance exercise decreases eIF2B{varepsilon} phosphorylation and potentiates the feeding-induced stimulation of p70S6K1 and rpS6 in young men Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2008; 295(2): R604 - R610. [Abstract] [Full Text] [PDF]

				M. Beelen, R. Koopman, A. P. Gijsen, H. Vandereyt, A. K. Kies, H. Kuipers, W. H. M. Saris, and L. J. C. van Loon Protein coingestion stimulates muscle protein synthesis during resistance-type exercise Am J Physiol Endocrinol Metab, July 1, 2008; 295(1): E70 - E77. [Abstract] [Full Text] [PDF]

				M. J. Drummond, H. C. Dreyer, B. Pennings, C. S. Fry, S. Dhanani, E. L. Dillon, M. Sheffield-Moore, E. Volpi, and B. B. Rasmussen Skeletal muscle protein anabolic response to resistance exercise and essential amino acids is delayed with aging J Appl Physiol, May 1, 2008; 104(5): 1452 - 1461. [Abstract] [Full Text] [PDF]

				H. C. Dreyer, M. J. Drummond, B. Pennings, S. Fujita, E. L. Glynn, D. L. Chinkes, S. Dhanani, E. Volpi, and B. B. Rasmussen Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle Am J Physiol Endocrinol Metab, February 1, 2008; 294(2): E392 - E400. [Abstract] [Full Text] [PDF]

				H. Mascher, J. Tannerstedt, T. Brink-Elfegoun, B. Ekblom, T. Gustafsson, and E. Blomstrand Repeated resistance exercise training induces different changes in mRNA expression of MAFbx and MuRF-1 in human skeletal muscle Am J Physiol Endocrinol Metab, January 1, 2008; 294(1): E43 - E51. [Abstract] [Full Text] [PDF]

				A H Manninen Hyperinsulinaemia, hyperaminoacidaemia and post-exercise muscle anabolism: the search for the optimal recovery drink Br. J. Sports Med., November 1, 2006; 40(11): 900 - 905. [Abstract] [Full Text] [PDF]

				L. Cynober and R. A. Harris Symposium on Branched-Chain Amino Acids: Conference Summary J. Nutr., January 1, 2006; 136(1): 333S - 336S. [Full Text] [PDF]