scholarly journals mTORC1 Signaling in Individual Human Muscle Fibers Following Resistance Exercise in Combination With Intake of Essential Amino Acids

2019 ◽  
Vol 6 ◽  
Author(s):  
Sebastian Edman ◽  
Karin Söderlund ◽  
Marcus Moberg ◽  
William Apró ◽  
Eva Blomstrand
Keyword(s):  
Amino Acids ◽  
Resistance Exercise ◽  
Muscle Fibers ◽  
Essential Amino Acids ◽  
Human Muscle ◽  
Mtorc1 Signaling ◽  
Individual Human

scholarly journals Intake Of Essential Amino Acids Stimulates Mtorc1 Signaling And Inhibits Autophagy Following Glycogen-depleted Resistance Exercise

2020 ◽  
Vol 52 (7S) ◽  
pp. 18-18
Author(s):  
William Apró ◽  
Oscar Horwath ◽  
Jonas Granberg ◽  
Marcus Moberg ◽  
Eva Andersson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Resistance Exercise ◽  
Essential Amino Acids ◽  
Mtorc1 Signaling

scholarly journals Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling

2009 ◽  
Vol 106 (4) ◽  
pp. 1374-1384 ◽  
Author(s):  
Micah J. Drummond ◽  
Hans C. Dreyer ◽  
Christopher S. Fry ◽  
Erin L. Glynn ◽  
Blake B. Rasmussen
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Human Skeletal Muscle ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Essential Amino Acids ◽  
Skeletal Muscle Protein ◽  
Mtorc1 Signaling

In this review we discuss current findings in the human skeletal muscle literature describing the acute influence of nutrients (leucine-enriched essential amino acids in particular) and resistance exercise on muscle protein synthesis and mammalian target of rapamycin complex 1 (mTORC1) signaling. We show that essential amino acids and an acute bout of resistance exercise independently stimulate human skeletal muscle protein synthesis. It also appears that ingestion of essential amino acids following resistance exercise leads to an even larger increase in the rate of muscle protein synthesis compared with the independent effects of nutrients or muscle contraction. Until recently the cellular mechanisms responsible for controlling the rate of muscle protein synthesis in humans were unknown. In this review, we highlight new studies in humans that have clearly shown the mTORC1 signaling pathway is playing an important regulatory role in controlling muscle protein synthesis in response to nutrients and/or muscle contraction. We propose that essential amino acid ingestion shortly following a bout of resistance exercise is beneficial in promoting skeletal muscle growth and may be useful in counteracting muscle wasting in a variety of conditions such as aging, cancer cachexia, physical inactivity, and perhaps during rehabilitation following trauma or surgery.

scholarly journals Activation of mTORC1 by leucine is potentiated by branched-chain amino acids and even more so by essential amino acids following resistance exercise

2016 ◽  
Vol 310 (11) ◽  
pp. C874-C884 ◽  
Author(s):  
Marcus Moberg ◽  
William Apró ◽  
Björn Ekblom ◽  
Gerrit van Hall ◽  
Hans-Christer Holmberg ◽  
...  
Keyword(s):  
Amino Acids ◽  
Resistance Exercise ◽  
Translation Initiation ◽  
Random Order ◽  
Essential Amino Acids ◽  
Branched Chain Amino Acids ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Mtorc1 Signaling ◽  
Branched Chain

Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mammalian target of rapamycin complex 1 (mTORC1) signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA, and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo, leucine, BCAA, or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise, and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6 kinase 1 (S6K1) was greater than at rest in all four trials (Placebo<Leucine<BCAA<EAA; P < 0.05 time × supplement), with a ninefold increase in the EAA trial. At this same time point, phosphorylation of eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) at Thr37/46 was unaffected by supplementation, while that of Thr46 alone exhibited a pattern similar to that of S6K1, being 18% higher with EAA than BCAA. However, after 180 min of recovery this difference between EAA and BCAA had disappeared, although with both these supplements the increases were still higher than with leucine (40%, P < 0.05) and placebo (100%, P < 0.05). In summary, EAA ingestion appears to stimulate translation initiation more effectively than the other supplements, although the results also suggest that this effect is primarily attributable to the BCAA.

Influence of fatty acids on ammonia and amino acid flux from active human muscle

1991 ◽  
Vol 261 (2) ◽  
pp. E168-E176 ◽  
Author(s):  
T. E. Graham ◽  
B. Kiens ◽  
M. Hargreaves ◽  
E. A. Richter
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Muscle Protein ◽  
Knee Extensor ◽  
Essential Amino Acids ◽  
Order Effect ◽  
Work Capacity ◽  
Human Muscle ◽  
Control Series ◽  
Ammonia Release

This study examined the dynamics of ammonia and amino acid exchange of human muscle during prolonged steady-state one-legged exercise at 80% of knee extensor maximal work capacity. Subjects (n = 10) performed leg extensor exercise for 1 h (control series), rested for 40 min while an infusion of Intralipid and heparin was begun, and then exercised the contralateral leg with the identical protocol [free fatty acid (FFA) series]. In the control series, ammonia efflux rose progressively, and 4.4 +/- 0.6 mmol were released in 1 h compared with 2.4 +/- 0.5 mmol (P less than 0.05) in the FFA series. The exercise was associated with large effluxes of total amino acids from the active muscle over the hour (12.8 +/- 4.3 and 10.3 +/- 3.3 mmol for control and FFA, respectively). Glutamine and alanine accounted for 47 and 64% of the efflux for the control and FFA series, respectively, while comparable values for essential amino acids were 24 and 20%. The latter implies that a net muscle protein catabolism was occurring during the exercise. The FFA treatment was associated not only with a reduced muscle ammonia release but also with a decreased (P less than 0.05) arterial concentration of nine amino acids (alanine, methionine, lysine, hydroxyproline, serine, glycine, proline, asparagine, and ornithine). Interpretation is limited due to the treatment order effect, but these data are compatible with the hypothesis that plasma clearance was affected by FFA.

Effects of an Amino Acid/Creatine Energy Supplement on the Acute Hormonal Response to Resistance Exercise

2007 ◽  
Vol 17 (6) ◽  
pp. 608-623 ◽  
Author(s):  
Nicholas A. Ratamess ◽  
Jay R. Hoffman ◽  
Ryan Ross ◽  
Miles Shanklin ◽  
Avery D. Faigenbaum ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Venous Blood ◽  
Area Under The Curve ◽  
Essential Amino Acids ◽  
Total Testosterone ◽  
Hormonal Response ◽  
Energy Supplement ◽  
And Performance

The authors aimed to examine the acute hormonal and performance responses to resistance exercise with and without prior consumption of an amino acid/creatine/energy supplement. Eight men performed a resistance-exercise protocol at baseline (BL), 20 min after consuming a supplement (S) consisting of essential amino acids, creatine, taurine, caffeine, and glucuronolactone or a maltodextrin placebo (P). Venous blood samples were obtained before and immediately after (IP), 15 min (15P), and 30 min (30P) after each protocol. Area under the curve of resistance-exercise volume revealed that BL was significantly less than S (10%) and P (8.6%). For fatigue rate, only S (18.4% ± 12.0%) was significantly lower than BL (32.9% ± 8.4%). Total testosterone (TT) and growth hormone (GH) were significantly elevated at IP and 15P in all conditions. The GH response was significantly lower, however, in S and P than in BL. The TT and GH responses did not differ between S and P. These results indicated that a supplement consisting of amino acids, creatine, taurine, caffeine, and glucuronolactone can modestly improve high-intensity endurance; however, the anabolic-hormonal response was not augmented.

scholarly journals Increased net muscle protein balance in response to simultaneous and separate ingestion of carbohydrate and essential amino acids following resistance exercise

2014 ◽  
Vol 39 (3) ◽  
pp. 329-339 ◽  
Author(s):  
Oliver C. Witard ◽  
Tara L. Cocke ◽  
Arny A. Ferrando ◽  
Robert R. Wolfe ◽  
Kevin D. Tipton
Keyword(s):  
Amino Acids ◽  
Resistance Exercise ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Exercise Bout ◽  
Essential Amino Acids ◽  
Delayed Response ◽  
Protein Balance ◽  
Post Exercise ◽  
Exercise Muscle

Relative to essential amino acids (EAAs), carbohydrate (CHO) ingestion stimulates a delayed response of net muscle protein balance (NBAL). We investigated if staggered ingestion of CHO and EAA would superimpose the response of NBAL following resistance exercise, thus resulting in maximal anabolic stimulation. Eight recreationally trained subjects completed 2 trials: combined (COMB — drink 1, CHO+EAA; drink 2, placebo) and separated (SEP — drink 1, CHO; drink 2, EAA) post-exercise ingestion of CHO and EAA. Drink 1 was administered 1 h following an acute exercise bout and was followed 1 h later by drink 2. A primed, continuous infusion of l-[ring-13C6]-phenylalanine was combined with femoral arteriovenous sampling and muscle biopsies for the determination of muscle protein kinetics. Arterial amino acid concentrations increased following ingestion of EAA in both conditions. No difference between conditions was observed for phenylalanine delivery to the leg (COMB: 167 ± 23 μmol·min−1·(100 mL leg vol)−1 × 6 h; SEP: 167 ± 21 μmol·min−1·(100 mL leg vol)−1 × 6 h, P > 0.05). In the first hour following ingestion of the drink containing EAA, phenylalanine uptake was 50% greater for the SEP trial than the COMB trial. However, phenylalanine uptake was similar for COMB (110 ± 19 mg) and SEP (117 ± 24 mg) over the 6 h period. These data suggest that whereas separation of CHO and EAA ingestion following exercise may have a transient physiological impact on NBAL, this response is not reflected over a longer period. Thus, separation of CHO and EAA ingestion is unnecessary to optimize post-exercise muscle protein metabolism.

scholarly journals Postexercise net protein synthesis in human muscle from orally administered amino acids

1999 ◽  
Vol 276 (4) ◽  
pp. E628-E634 ◽  
Author(s):  
Kevin D. Tipton ◽  
Arny A. Ferrando ◽  
Stuart M. Phillips ◽  
David Doyle ◽  
Robert R. Wolfe
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Random Order ◽  
Essential Amino Acids ◽  
Constant Infusion ◽  
Protein Balance

We examined the response of net muscle protein synthesis to ingestion of amino acids after a bout of resistance exercise. A primed, constant infusion ofl-[ 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 ⋅ min−1 ⋅ 100 ml leg volume−1) to positive during MAA ingestion (17 ± 13 nmol ⋅ min−1 ⋅ 100 ml leg volume−1) and EAA (29 ± 14 nmol ⋅ min−1 ⋅ 100 ml leg volume−1; 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.

scholarly journals Intake of branched-chain or essential amino acids attenuates the elevation in muscle levels of PGC-1α4 mRNA caused by resistance exercise

2016 ◽  
Vol 311 (1) ◽  
pp. E246-E251 ◽  
Author(s):  
Hedvig Samuelsson ◽  
Marcus Moberg ◽  
William Apró ◽  
Björn Ekblom ◽  
Eva Blomstrand
Keyword(s):  
Amino Acids ◽  
Protein Kinase ◽  
Resistance Exercise ◽  
Vastus Lateralis ◽  
Essential Amino Acids ◽  
Mitogen Activated Protein Kinase ◽  
Vastus Lateralis Muscle ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Branched Chain

The transcriptional coactivator peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is recognized as the master regulator of mitochondrial biogenesis. However, recently a novel isoform, PGC-1α4, that specifically regulates muscle hypertrophy was discovered. Because stimulation of mechanistic target of rapamycin complex 1 (mTORC1) activity is tightly coupled to hypertrophy, we hypothesized that activation of this pathway would upregulate PGC-1α4. Eight male subjects performed heavy resistance exercise (10 × 8–12 repetitions at ∼75% of 1 repetition maximum in leg press) on four different occasions, ingesting in random order a solution containing essential amino acids (EAA), branched-chain amino acids (BCAA), leucine, or flavored water (placebo) during and after the exercise. Biopsies were taken from the vastus lateralis muscle before and immediately after exercise, as well as following 90 and 180 min of recovery. Signaling through mTORC1, as reflected in p70S6 kinase phosphorylation, was stimulated to a greater extent by the EAA and BCAA than the leucine or placebo supplements. Unexpectedly, intake of EAA or BCAA attenuated the stimulatory effect of exercise on PGC-1α4 expression by ∼50% (from a 10- to 5-fold increase with BCAA and EAA, P < 0.05) 3 h after exercise, whereas intake of leucine alone did not reduce this response. The 60% increase ( P < 0.05) in the level of PGC-1α1 mRNA 90 min after exercise was uninfluenced by amino acid intake. Muscle glycogen levels were reduced and AMP-activated protein kinase α2 activity and phosphorylation of p38 mitogen-activated protein kinase enhanced to the same extent with all four supplements. In conclusion, induction of PGC-1α4 does not appear to regulate the nutritional (BCAA or EAA)-mediated activation of mTORC1 in human muscle.

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