|
|
||||||||
Departments of 1Physical Therapy, 2Internal Medicine, and 3Surgery, 4Division of Rehabilitation Sciences, University of Texas Medical Branch, Galveston, Texas
Submitted 7 September 2007 ; accepted in final form 3 December 2007
We recently showed that resistance exercise and ingestion of essential amino acids with carbohydrate (EAA+CHO) can independently stimulate mammalian target of rapamycin (mTOR) signaling and muscle protein synthesis in humans. Providing an EAA+CHO solution postexercise can further increase muscle protein synthesis. Therefore, we hypothesized that enhanced mTOR signaling might be responsible for the greater muscle protein synthesis when leucine-enriched EAA+CHOs are ingested during postexercise recovery. Sixteen male subjects were randomized to one of two groups (control or EAA+CHO). The EAA+CHO group ingested the nutrient solution 1 h after resistance exercise. mTOR signaling was assessed by immunoblotting from repeated muscle biopsy samples. Mixed muscle fractional synthetic rate (FSR) was measured using stable isotope techniques. Muscle protein synthesis and 4E-BP1 phosphorylation during exercise were significantly reduced (P < 0.05). Postexercise FSR was elevated above baseline in both groups at 1 h but was even further elevated in the EAA+CHO group at 2 h postexercise (P < 0.05). Increased FSR was associated with enhanced phosphorylation of mTOR and S6K1 (P < 0.05). Akt phosphorylation was elevated at 1 h and returned to baseline by 2 h in the control group, but it remained elevated in the EAA+CHO group (P < 0.05). 4E-BP1 phosphorylation returned to baseline during recovery in control but became elevated when EAA+CHO was ingested (P < 0.05). eEF2 phosphorylation decreased at 1 and 2 h postexercise to a similar extent in both groups (P < 0.05). Our data suggest that enhanced activation of the mTOR signaling pathway is playing a role in the greater synthesis of muscle proteins when resistance exercise is followed by EAA+CHO ingestion.
muscle protein synthesis; mammalian target of rapamycin; essential amino acids
This article has been cited by other articles:
![]() |
R. Koopman and L. J. C. van Loon Aging, exercise, and muscle protein metabolism J Appl Physiol, June 1, 2009; 106(6): 2040 - 2048. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Kumar, P. Atherton, K. Smith, and M. J. Rennie Human muscle protein synthesis and breakdown during and after exercise J Appl Physiol, June 1, 2009; 106(6): 2026 - 2039. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Fujita, H. C. Dreyer, M. J. Drummond, E. L. Glynn, E. Volpi, and B. B. Rasmussen Essential amino acid and carbohydrate ingestion before resistance exercise does not enhance postexercise muscle protein synthesis J Appl Physiol, May 1, 2009; 106(5): 1730 - 1739. [Abstract] [Full Text] [PDF] |
||||
![]() |
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] |
||||
![]() |
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] |
||||
![]() |
M. Miyazaki and K. A. Esser Cellular mechanisms regulating protein synthesis and skeletal muscle hypertrophy in animals J Appl Physiol, April 1, 2009; 106(4): 1367 - 1373. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. Drummond, H. C. Dreyer, C. S. Fry, E. L. Glynn, and B. B. Rasmussen Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling J Appl Physiol, April 1, 2009; 106(4): 1374 - 1384. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. Drummond, C. S. Fry, E. L. Glynn, H. C. Dreyer, S. Dhanani, K. L. Timmerman, E. Volpi, and B. B. Rasmussen Rapamycin administration in humans blocks the contraction-induced increase in skeletal muscle protein synthesis J. Physiol., April 1, 2009; 587(7): 1535 - 1546. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. R. Moore, J. E. Tang, N. A. Burd, T. Rerecich, M. A. Tarnopolsky, and S. M. Phillips Differential stimulation of myofibrillar and sarcoplasmic protein synthesis with protein ingestion at rest and after resistance exercise J. Physiol., February 15, 2009; 587(4): 897 - 904. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. R Moore, M. J Robinson, J. L Fry, J. E Tang, E. I Glover, S. B Wilkinson, T. Prior, M. A Tarnopolsky, and S. M Phillips Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men Am. J. Clinical Nutrition, January 1, 2009; 89(1): 161 - 168. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. I. Glover, S. M. Phillips, B. R. Oates, J. E. Tang, M. A. Tarnopolsky, A. Selby, K. Smith, and M. J. Rennie Immobilization induces anabolic resistance in human myofibrillar protein synthesis with low and high dose amino acid infusion J. Physiol., December 15, 2008; 586(24): 6049 - 6061. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. C. Dreyer, M. J. Drummond, E. L. Glynn, S. Fujita, D. L. Chinkes, E. Volpi, and B. B. Rasmussen Resistance exercise increases human skeletal muscle AS160/TBC1D4 phosphorylation in association with enhanced leg glucose uptake during postexercise recovery J Appl Physiol, December 1, 2008; 105(6): 1967 - 1974. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. Drummond, J. J. McCarthy, C. S. Fry, K. A. Esser, and B. B. Rasmussen Aging differentially affects human skeletal muscle microRNA expression at rest and after an anabolic stimulus of resistance exercise and essential amino acids Am J Physiol Endocrinol Metab, December 1, 2008; 295(6): E1333 - E1340. [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] |
||||
![]() |
S. B. Wilkinson, S. M. Phillips, P. J. Atherton, R. Patel, K. E. Yarasheski, M. A. Tarnopolsky, and M. J. Rennie Differential effects of resistance and endurance exercise in the fed state on signalling molecule phosphorylation and protein synthesis in human muscle J. Physiol., August 1, 2008; 586(15): 3701 - 3717. [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] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |