We examined the response of net muscle protein synthesis to ingestion of amino acids after a bout of resistance exercise. A primed, constant infusion of L-[ring-²H₅]phenylalanine was used to measure net muscle protein balance in three male and three female volunteers on three occasions. Subjects consumed in random order 1 liter of 1) a mixed amino acid (40 g) solution (MAA), 2) an essential amino acid (40 g) solution (EAA), and 3) a placebo solution (PLA). Arterial amino acid concentrations increased ~150-640% above baseline during ingestion of MAA and EAA. Net muscle protein balance was significantly increased from negative during PLA ingestion (50 ± 23 nmol · min¹ · 100 ml leg volume¹) to positive during MAA ingestion (17 ± 13 nmol · min¹ · 100 ml leg volume¹) and EAA (29 ± 14 nmol · min¹ · 100 ml leg volume¹; P < 0.05). Because net balance was similar for MAA and EAA, it does not appear necessary to include nonessential amino acids in a formulation designed to elicit an anabolic response from muscle after exercise. We concluded that ingestion of oral essential amino acids results in a change from net muscle protein degradation to net muscle protein synthesis after heavy resistance exercise in humans similar to that seen when the amino acids were infused.

muscle protein synthesis; muscle protein breakdown; resistance exercise; stable isotopes

This article has been cited by other articles:

				H. G. Gasier, S. E. Riechman, M. P. Wiggs, S. F. Previs, and J. D. Fluckey A comparison of 2H2O and phenylalanine flooding dose to investigate muscle protein synthesis with acute exercise in rats Am J Physiol Endocrinol Metab, July 1, 2009; 297(1): E252 - E259. [Abstract] [Full Text] [PDF]

				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]

				K. R. Howarth, N. A. Moreau, S. M. Phillips, and M. J. Gibala Coingestion of protein with carbohydrate during recovery from endurance exercise stimulates skeletal muscle protein synthesis in humans J Appl Physiol, April 1, 2009; 106(4): 1394 - 1402. [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. Rennie, S. Phillips, and K. Smith Reliability of results and interpretation of measures of 3-methylhistidine in muscle interstitium as marker of muscle proteolysis J Appl Physiol, October 1, 2008; 105(4): 1380 - 1381. [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]

				N. Brooks, G. J. Cloutier, S. M. Cadena, J. E. Layne, C. A. Nelsen, A. M. Freed, R. Roubenoff, and C. Castaneda-Sceppa Resistance training and timed essential amino acids protect against the loss of muscle mass and strength during 28 days of bed rest and energy deficit J Appl Physiol, July 1, 2008; 105(1): 241 - 248. [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]

				J. E. Tang, J. G. Perco, D. R. Moore, S. B. Wilkinson, and S. M. Phillips Resistance training alters the response of fed state mixed muscle protein synthesis in young men Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2008; 294(1): R172 - R178. [Abstract] [Full Text] [PDF]

				R. Koopman, M. Beelen, T. Stellingwerff, B. Pennings, W. H. M. Saris, A. K. Kies, H. Kuipers, and L. J. C. van Loon Coingestion of carbohydrate with protein does not further augment postexercise muscle protein synthesis Am J Physiol Endocrinol Metab, September 1, 2007; 293(3): E833 - E842. [Abstract] [Full Text] [PDF]

				S. D. R. Harridge Plasticity of human skeletal muscle: gene expression to in vivo function Exp Physiol, September 1, 2007; 92(5): 783 - 797. [Abstract] [Full Text] [PDF]

				K. D. Tipton, T. A. Elliott, M. G. Cree, A. A. Aarsland, A. P. Sanford, and R. R. Wolfe Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise Am J Physiol Endocrinol Metab, January 1, 2007; 292(1): E71 - E76. [Abstract] [Full Text] [PDF]

				D. J. Cuthbertson, J. Babraj, K. Smith, E. Wilkes, M. J. Fedele, K. Esser, and M. Rennie Anabolic signaling and protein synthesis in human skeletal muscle after dynamic shortening or lengthening exercise Am J Physiol Endocrinol Metab, April 1, 2006; 290(4): E731 - E738. [Abstract] [Full Text] [PDF]

				E. Borsheim, H. Kobayashi, D. L. Traber, and R. R. Wolfe Compartmental distribution of amino acids during hemodialysis-induced hypoaminoacidemia Am J Physiol Endocrinol Metab, April 1, 2006; 290(4): E643 - E652. [Abstract] [Full Text] [PDF]

				J. A. Babraj, D. J. R. Cuthbertson, K. Smith, H. Langberg, B. Miller, M. R. Krogsgaard, M. Kjaer, and M. J. Rennie Collagen synthesis in human musculoskeletal tissues and skin Am J Physiol Endocrinol Metab, November 1, 2005; 289(5): E864 - E869. [Abstract] [Full Text] [PDF]

				D. R. Bolster, M. A. Pikosky, P. C. Gaine, W. Martin, R. R. Wolfe, K. D. Tipton, D. Maclean, C. M. Maresh, and N. R. Rodriguez Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise Am J Physiol Endocrinol Metab, October 1, 2005; 289(4): E678 - E683. [Abstract] [Full Text] [PDF]

				M. Sheffield-Moore, D. Paddon-Jones, A. P. Sanford, J. I. Rosenblatt, A. G. Matlock, M. G. Cree, and R. R. Wolfe Mixed muscle and hepatic derived plasma protein metabolism is differentially regulated in older and younger men following resistance exercise Am J Physiol Endocrinol Metab, May 1, 2005; 288(5): E922 - E929. [Abstract] [Full Text] [PDF]

				R. G. Highstead, K. D. Tipton, D. L. Creson, R. R. Wolfe, and A. A. Ferrando Incidence of associated events during the performance of invasive procedures in healthy human volunteers J Appl Physiol, April 1, 2005; 98(4): 1202 - 1206. [Abstract] [Full Text] [PDF]

				R. Koopman, A. J. M. Wagenmakers, R. J. F. Manders, A. H. G. Zorenc, J. M. G. Senden, M. Gorselink, H. A. Keizer, and L. J. C. van Loon Combined ingestion of protein and free leucine with carbohydrate increases postexercise muscle protein synthesis in vivo in male subjects Am J Physiol Endocrinol Metab, April 1, 2005; 288(4): E645 - E653. [Abstract] [Full Text] [PDF]

				W. J. Durham, S. L. Miller, C. W. Yeckel, D. L. Chinkes, K. D. Tipton, B. B. Rasmussen, and R. R. Wolfe Leg glucose and protein metabolism during an acute bout of resistance exercise in humans J Appl Physiol, October 1, 2004; 97(4): 1379 - 1386. [Abstract] [Full Text] [PDF]

				R. Koopman, D. L. E. Pannemans, A. E. Jeukendrup, A. P. Gijsen, J. M. G. Senden, D. Halliday, W. H. M. Saris, L. J. C. van Loon, and A. J. M. Wagenmakers Combined ingestion of protein and carbohydrate improves protein balance during ultra-endurance exercise Am J Physiol Endocrinol Metab, October 1, 2004; 287(4): E712 - E720. [Abstract] [Full Text] [PDF]

				D. Paddon-Jones, E. Borsheim, and R. R. Wolfe Potential Ergogenic Effects of Arginine and Creatine Supplementation J. Nutr., October 1, 2004; 134(10): 2888S - 2894S. [Abstract] [Full Text] [PDF]

				E. Borsheim, M. G. Cree, K. D. Tipton, T. A. Elliott, A. Aarsland, and R. R. Wolfe Effect of carbohydrate intake on net muscle protein synthesis during recovery from resistance exercise J Appl Physiol, February 1, 2004; 96(2): 674 - 678. [Abstract] [Full Text] [PDF]

				W. Derave, B. O. Eijnde, P. Verbessem, M. Ramaekers, M. Van Leemputte, E. A. Richter, and P. Hespel Combined creatine and protein supplementation in conjunction with resistance training promotes muscle GLUT-4 content and glucose tolerance in humans J Appl Physiol, May 1, 2003; 94(5): 1910 - 1916. [Abstract] [Full Text] [PDF]

				D. K. Layman The Role of Leucine in Weight Loss Diets and Glucose Homeostasis J. Nutr., January 1, 2003; 133(1): 261S - 267. [Abstract] [Full Text] [PDF]

				K. D. Tipton, E. Borsheim, S. E. Wolf, A. P. Sanford, and R. R. Wolfe Acute response of net muscle protein balance reflects 24-h balance after exercise and amino acid ingestion Am J Physiol Endocrinol Metab, January 1, 2003; 284(1): E76 - E89. [Abstract] [Full Text] [PDF]

				E. Borsheim, K. D. Tipton, S. E. Wolf, and R. R. Wolfe Essential amino acids and muscle protein recovery from resistance exercise Am J Physiol Endocrinol Metab, October 1, 2002; 283(4): E648 - E657. [Abstract] [Full Text] [PDF]

				H. Fouillet, C. Bos, C. Gaudichon, and D. Tome Approaches to Quantifying Protein Metabolism in Response to Nutrient Ingestion J. Nutr., October 1, 2002; 132(10): 3208S - 3218. [Abstract] [Full Text] [PDF]

				M. J. Rennie, J. Bohe, and R. R. Wolfe Latency, Duration and Dose Response Relationships of Amino Acid Effects on Human Muscle Protein Synthesis J. Nutr., October 1, 2002; 132(10): 3225S - 3227. [Abstract] [Full Text] [PDF]

				S. R. Kimball, P. A. Farrell, and L. S. Jefferson Exercise Effects on Muscle Insulin Signaling and Action: Invited Review: Role of insulin in translational control of protein synthesis in skeletal muscle by amino acids or exercise J Appl Physiol, September 1, 2002; 93(3): 1168 - 1180. [Abstract] [Full Text] [PDF]

				J.-C. J. Bouthegourd, S. M. Roseau, L. Makarios-Lahham, P. M. Leruyet, D. G. Tome, and P. C. Even A preexercise alpha -lactalbumin-enriched whey protein meal preserves lipid oxidation and decreases adiposity in rats Am J Physiol Endocrinol Metab, September 1, 2002; 283(3): E565 - E572. [Abstract] [Full Text] [PDF]

				M. Korach-Andre, Y. Burelle, F. Peronnet, D. Massicotte, C. Lavoie, and C. Hillaire-Marcel Differential metabolic fate of the carbon skeleton and amino-N of [13C]alanine and [15N]alanine ingested during prolonged exercise J Appl Physiol, August 1, 2002; 93(2): 499 - 504. [Abstract] [Full Text] [PDF]

				G. Parise, S. Mihic, D. MacLennan, K. E. Yarasheski, and M. A. Tarnopolsky Effects of acute creatine monohydrate supplementation on leucine kinetics and mixed-muscle protein synthesis J Appl Physiol, September 1, 2001; 91(3): 1041 - 1047. [Abstract] [Full Text] [PDF]

				K. D. Tipton, B. B. Rasmussen, S. L. Miller, S. E. Wolf, S. K. Owens-Stovall, B. E. Petrini, and R. R. Wolfe Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise Am J Physiol Endocrinol Metab, August 1, 2001; 281(2): E197 - E206. [Abstract] [Full Text] [PDF]

				H. Fouillet, C. Gaudichon, F. Mariotti, C. Bos, J. F. Huneau, and D. Tome Energy nutrients modulate the splanchnic sequestration of dietary nitrogen in humans: a compartmental analysis Am J Physiol Endocrinol Metab, August 1, 2001; 281(2): E248 - E260. [Abstract] [Full Text] [PDF]

				L. J. C. van Loon, M. Kruijshoop, H. Verhagen, W. H. M. Saris, and A. J. M. Wagenmakers Ingestion of Protein Hydrolysate and Amino Acid-Carbohydrate Mixtures Increases Postexercise Plasma Insulin Responses in Men J. Nutr., October 1, 2000; 130(10): 2508 - 2513. [Abstract] [Full Text]

				P. W.R. Lemon Beyond the Zone: Protein Needs of Active Individuals J. Am. Coll. Nutr., October 1, 2000; 19(90005): 513S - 521. [Abstract] [Full Text] [PDF]

				B. B. Rasmussen, K. D. Tipton, S. L. Miller, S. E. Wolf, and R. R. Wolfe An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise J Appl Physiol, February 1, 2000; 88(2): 386 - 392. [Abstract] [Full Text] [PDF]

				M. Sheffield-Moore, R. R. Wolfe, D. C. Gore, S. E. Wolf, D. M. Ferrer, and A. A. Ferrando Combined effects of hyperaminoacidemia and oxandrolone on skeletal muscle protein synthesis Am J Physiol Endocrinol Metab, February 1, 2000; 278(2): E273 - E279. [Abstract] [Full Text] [PDF]

				T. A. Trappe, F. White, C. P. Lambert, D. Cesar, M. Hellerstein, and W. J. Evans Effect of ibuprofen and acetaminophen on postexercise muscle protein synthesis Am J Physiol Endocrinol Metab, March 1, 2002; 282(3): E551 - E556. [Abstract] [Full Text] [PDF]