Enhanced rates of muscle protein synthesis and elevated mTOR signalling following endurance exercise in human subjects

ABSTRACT Background Protein ingestion increases skeletal muscle protein synthesis rates during recovery from endurance exercise. Objectives We aimed to determine the effect of graded doses of dietary protein co-ingested with carbohydrate on whole-body protein metabolism, and skeletal muscle myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis rates during recovery from endurance exercise. Methods In a randomized, double-blind, parallel-group design, 48 healthy, young, endurance-trained men (mean ± SEM age: 27 ± 1 y) received a primed continuous infusion of l-[ring-2H5]-phenylalanine, l-[ring-3,5-2H2]-tyrosine, and l-[1-13C]-leucine and ingested 45 g carbohydrate with either 0 (0 g PRO), 15 (15 g PRO), 30 (30 g PRO), or 45 (45 g PRO) g intrinsically l-[1-13C]-phenylalanine and l-[1-13C]-leucine labeled milk protein after endurance exercise. Blood and muscle biopsy samples were collected over 360 min of postexercise recovery to assess whole-body protein metabolism and both MyoPS and MitoPS rates. Results Protein intake resulted in ∼70%–74% of the ingested protein-derived phenylalanine appearing in the circulation. Whole-body net protein balance increased dose-dependently after ingestion of 0, 15, 30, or 45 g protein (mean ± SEM: −0.31± 0.16, 5.08 ± 0.21, 10.04 ± 0.30, and 13.49 ± 0.55 μmol phenylalanine · kg−1 · h−1, respectively; P < 0.001). 30 g PRO stimulated a ∼46% increase in MyoPS rates (%/h) compared with 0 g PRO and was sufficient to maximize MyoPS rates after endurance exercise. MitoPS rates were not increased after protein ingestion; however, incorporation of dietary protein–derived l-[1-13C]-phenylalanine into de novo mitochondrial protein increased dose-dependently after ingestion of 15, 30, and 45 g protein at 360 min postexercise (0.018 ± 0.002, 0.034 ± 0.002, and 0.046 ± 0.003 mole percentage excess, respectively; P < 0.001). Conclusions Protein ingested after endurance exercise is efficiently digested and absorbed into the circulation. Whole-body net protein balance and dietary protein–derived amino acid incorporation into mitochondrial protein respond to increasing protein intake in a dose-dependent manner. Ingestion of 30 g protein is sufficient to maximize MyoPS rates during recovery from a single bout of endurance exercise. This trial was registered at trialregister.nl as NTR5111.

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Effects Of Whey, Casein, Or Milk Protein Ingestion On Muscle Protein Synthesis After Endurance Exercise

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000493467.45353.8e ◽

2014 ◽

Vol 46 ◽

pp. 99

Author(s):

Atsushi Kanda ◽

Kyosuke Nakayama ◽

Chiaki Sanbongi ◽

Masashi Nagata ◽

Shuji Ikegami ◽

...

Keyword(s):

Protein Synthesis ◽

Endurance Exercise ◽

Milk Protein ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Protein Ingestion

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Post-exercise whey protein hydrolysate supplementation induces a greater increase in muscle protein synthesis than its constituent amino acid content

British Journal Of Nutrition ◽

10.1017/s0007114512006174 ◽

2013 ◽

Vol 110 (6) ◽

pp. 981-987 ◽

Cited By ~ 29

Author(s):

Atsushi Kanda ◽

Kyosuke Nakayama ◽

Tomoyuki Fukasawa ◽

Jinichiro Koga ◽

Minoru Kanegae ◽

...

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Amino Acid ◽

Whey Protein ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Acid Mixture ◽

Post Exercise ◽

The Impact ◽

Mtor Signalling

It is well known that ingestion of a protein source is effective in stimulating muscle protein synthesis after exercise. In addition, there are numerous reports on the impact of leucine and leucine-rich whey protein on muscle protein synthesis and mammalian target of rapamycin (mTOR) signalling. However, there is only limited information on the effects of whey protein hydrolysates (WPH) on muscle protein synthesis and mTOR signalling. The aim of the present study was to compare the effects of WPH and amino acids on muscle protein synthesis and the initiation of translation in skeletal muscle during the post-exercise phase. Male Sprague–Dawley rats swam for 2 h to depress muscle protein synthesis. Immediately after exercise, the animals were administered either carbohydrate (CHO), CHO plus an amino acid mixture (AA) or CHO plus WPH. At 1 h after exercise, the supplements containing whey-based protein (AA and WPH) caused a significant increase in the fractional rate of protein synthesis (FSR) compared with CHO. WPH also caused a significant increase in FSR compared with AA. Post-exercise ingestion of WPH caused a significant increase in the phosphorylation of mTOR levels compared with AA or CHO. In addition, WPH caused greater phosphorylation of ribosomal protein S6 kinase and eukaryotic initiation factor 4E-binding protein 1 than AA and CHO. In contrast, there was no difference in plasma amino acid levels following supplementation with either AA or WPH. These results indicate that WPH may include active components that are superior to amino acids for stimulating muscle protein synthesis and initiating translation.

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Protein–Leucine Fed Dose Effects on Muscle Protein Synthesis after Endurance Exercise

Medicine & Science in Sports & Exercise ◽

10.1249/mss.0000000000000447 ◽

2015 ◽

Vol 47 (3) ◽

pp. 547-555 ◽

Cited By ~ 38

Author(s):

DAVID S. ROWLANDS ◽

ANDRE R. NELSON ◽

STUART M. PHILLIPS ◽

JAMES A. FAULKNER ◽

JIM CLARKE ◽

...

Keyword(s):

Protein Synthesis ◽

Endurance Exercise ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Dose Effects

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Dietary protein and exercise training in ageing

Proceedings of The Nutrition Society ◽

10.1017/s0029665110003927 ◽

2010 ◽

Vol 70 (1) ◽

pp. 104-113 ◽

Cited By ~ 28

Author(s):

René Koopman

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Exercise Training ◽

Muscle Mass ◽

Skeletal Muscle Mass ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Human Subjects ◽

The Elderly ◽

Age Related

Ageing is accompanied by a progressive loss of skeletal muscle mass and strength, leading to the loss of functional capacity and an increased risk for developing chronic metabolic diseases such as diabetes. The age-related loss of skeletal muscle mass results from a chronic disruption in the balance between muscle protein synthesis and degradation. As basal muscle protein synthesis rates are likely not different between healthy young and elderly human subjects, it was proposed that muscles from older adults lack the ability to regulate the protein synthetic response to anabolic stimuli, such as food intake and physical activity. Indeed, the dose–response relationship between myofibrillar protein synthesis and the availability of essential amino acids and/or resistance exercise intensity is shifted down and to the right in elderly human subjects. This so-called ‘anabolic resistance’ represents a key factor responsible for the age-related decline in skeletal muscle mass. Interestingly, long-term resistance exercise training is effective as a therapeutic intervention to augment skeletal muscle mass, and improves functional performance in the elderly. The consumption of different types of proteins, i.e. protein hydrolysates, can have different stimulatory effects on muscle protein synthesis in the elderly, which may be due to their higher rate of digestion and absorption. Current research aims to elucidate the interactions between nutrition, exercise and the skeletal muscle adaptive response that will define more effective strategies to maximise the therapeutic benefits of lifestyle interventions in the elderly.

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Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00060.2005 ◽

2005 ◽

Vol 289 (4) ◽

pp. E678-E683 ◽

Cited By ~ 52

Author(s):

Douglas R. Bolster ◽

Matthew A. Pikosky ◽

P. Courtney Gaine ◽

William Martin ◽

Robert R. Wolfe ◽

...

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Endurance Exercise ◽

Dietary Protein ◽

Protein Intake ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Dietary Protein Intake ◽

Skeletal Muscle Protein ◽

Skeletal Muscle Protein Synthesis

This investigation evaluated the physiological impact of different dietary protein intakes on skeletal muscle protein synthesis postexercise in endurance runners. Five endurance-trained, male runners participated in a randomized, crossover design diet intervention, where they consumed either a low (0.8 g/kg; LP)-, moderate (1.8 g/kg; MP)-, or high (3.6 g/kg; HP)-protein diet for 4 wk. Diets were designed to be eucaloric with carbohydrate, fat, and protein approximating 60, 30, and 10%; 55, 30, and 15%; and 40, 30, and 30% for LP, MP, and HP, respectively. Substrate oxidation was assessed via indirect calorimetry at 3 wk of the dietary interventions. Mixed-muscle protein fractional synthetic rate (FSR) was measured after an endurance run (75 min at 70% V̇o2 peak) using a primed, continuous infusion of [2H5]phenylalanine. Protein oxidation increased with increasing protein intake, with each trial being significantly different from the other ( P < 0.01). FSR after exercise was significantly greater for LP (0.083%/h) and MP (0.078%/h) than for HP (0.052%/h; P < 0.05). There was no difference in FSR between LP and MP. This is the first investigation to establish that habitual dietary protein intake in humans modulates skeletal muscle protein synthesis after an endurance exercise bout. Future studies directed at mechanisms by which level of protein intake influences skeletal muscle turnover are needed.

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Coingestion of protein with carbohydrate during recovery from endurance exercise stimulates skeletal muscle protein synthesis in humans

Yearbook of Sports Medicine ◽

10.1016/s0162-0908(09)79509-1 ◽

2010 ◽

Vol 2010 ◽

pp. 163-165

Author(s):

D.C. Nieman

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Endurance Exercise ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Skeletal Muscle Protein ◽

Skeletal Muscle Protein Synthesis

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Muscle protein metabolism in female swimmers after a combination of resistance and endurance exercise

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.5.2034 ◽

1996 ◽

Vol 81 (5) ◽

pp. 2034-2038 ◽

Cited By ~ 75

Author(s):

Kevin D. Tipton ◽

Arny A. Ferrando ◽

Bradley D. Williams ◽

Robert R. Wolfe

Keyword(s):

Protein Synthesis ◽

Resistance Training ◽

Endurance Exercise ◽

Protein Metabolism ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Whole Body ◽

Protein Breakdown ◽

Body Protein ◽

Muscle Protein Metabolism

Tipton, Kevin D., Arny A. Ferrando, Bradley D. Williams, and Robert R. Wolfe. Muscle protein metabolism in female swimmers after a combination of resistance and endurance exercise. J. Appl. Physiol. 81(5): 2034–2038, 1996.—There is little known about the responses of muscle protein metabolism in women to exercise. Furthermore, the effect of adding resistance training to an endurance training regimen on net protein anabolism has not been established in either men or women. The purpose of this study was to quantify the acute effects of combined swimming and resistance training on protein metabolism in female swimmers by the direct measurement of muscle protein synthesis and whole body protein degradation. Seven collegiate female swimmers were each studied on four separate occasions with a primed constant infusion of ring-[13C6]phenylalanine (Phe) to measure the fractional synthetic rate (FSR) of the posterior deltoid and whole body protein breakdown. Measurements were made over a 5-h period at rest and after each of three randomly ordered workouts: 1) 4,600 m of intense interval swimming (SW); 2) a whole body resistance-training workout with no swimming on that day (RW); and 3) swimming and resistance training combined (SR). Whole body protein breakdown was similar for all treatments (0.75 ± 0.04, 0.69 ± 0.03, 0.69 ± 0.02, and 0.71 ± 0.04 μmol ⋅ min−1 ⋅ kg−1for rest, RW, SW, and SR, respectively). The FSR of the posterior deltoid was significantly greater ( P< 0.05) after SR (0.082 ± 0.015%/h) than at rest (0.045 ± 0.006%/h). There was no significant difference in the FSR after RW (0.048 ± 0.004%/h) or SW (0.064 ± 0.008%/h) from rest or from SR. These data indicate that the combination of swimming and resistance exercise stimulates net muscle protein synthesis above resting levels in female swimmers.

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