Influence of nutrient ingestion on amino acid transporters and protein synthesis in human skeletal muscle after sprint exercise

2017 ◽  
Vol 123 (6) ◽  
pp. 1501-1515 ◽  
Author(s):  
Håkan C. Rundqvist ◽  
Mona Esbjörnsson ◽  
Olav Rooyackers ◽  
Ted Österlund ◽  
Marcus Moberg ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Amino Acid Transporter ◽  
Mtor Signaling ◽  
Sprint Exercise ◽  
Phosphorylated Akt ◽  
Acid Transporter

Nutrient ingestion is known to increase the exercise-induced stimulation of muscle protein synthesis following resistance exercise. Less is known about the effect of nutrients on muscle protein synthesis following sprint exercise. At two occasions separated by 1 mo, 12 healthy subjects performed three 30-s sprints with 20-min rest between bouts. In randomized order, they consumed a drink with essential amino acids and maltodextrin (nutrient) or flavored water (placebo). Muscle biopsies were obtained 80 and 200 min after the last sprint, and blood samples were taken repeatedly during the experiment. Fractional synthetic rate (FSR) was measured by continuous infusion of l-[2H5]phenylalanine up to 200 min postexercise. The mRNA expression and protein expression of SNAT2 were both 1.4-fold higher ( P < 0.05) after nutrient intake compared with placebo at 200 min postexercise. Phosphorylated Akt, mammalian target of rapamycin (mTOR), and p70S6k were 1.7- to 3.6-fold higher ( P < 0.01) 80 min after the last sprint with nutrient ingestion as compared with placebo. In addition, FSR was higher ( P < 0.05) with nutrients when plasma phenylalanine (FSRplasma) was used as a precursor but not when intracellular phenylalanine (FSRmuscle) was used. Significant correlations were also found between FSRplasma on the one hand and plasma leucine and serum insulin on the other hand in the nutrient condition. The results show that nutrient ingestion induces the expression of the amino acid transporter SNAT2 stimulates Akt/mTOR signaling and most likely the rate of muscle protein synthesis following sprint exercise. NEW & NOTEWORTHY There is limited knowledge regarding the effect of nutrients on muscle protein synthesis following sprint as compared with resistance exercise. The results demonstrate that nutrient ingestion during repeated 30-s bouts of sprint exercise induces expression of the amino acid transporter SNAT2 and stimulates Akt/mTOR signaling and most likely the rate of muscle protein synthesis. Future studies to explore the chronic effects of nutritional ingestion during sprint exercise sessions on muscle mass accretion are warranted.

scholarly journals Exercise May Promote Skeletal Muscle Hypertrophy via Enhancing Leucine-Sensing: Preliminary Evidence

2021 ◽  
Vol 12 ◽  
Author(s):  
Yan Zhao ◽  
Jason Cholewa ◽  
Huayu Shang ◽  
Yueqin Yang ◽  
Xiaomin Ding ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Protein Concentration ◽  
Muscle Hypertrophy ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Muscle Fibers ◽  
Mtor Signaling ◽  
Treadmill Running

Several studies have indicated a positive effect of exercise (especially resistance exercise) on the mTOR signaling that control muscle protein synthesis and muscle remodeling. However, the relationship between exercise, mTOR activation and leucine-sensing requires further clarification. Two month old Sprague-Dawley rats were subjected to aerobic exercise (treadmill running at 20 m/min, 6° incline for 60 min) and resistance exercise (incremental ladder climbing) for 4 weeks. The gastrocnemius muscles were removed for determination of muscle fibers diameter, cross-sectional area (CSA), protein concentration and proteins involved in muscle leucine-sensing and protein synthesis. The results show that 4 weeks of resistance exercise increased the diameter and CSA of gastrocnemius muscle fibers, protein concentration, the phosphorylation of mTOR (Ser2448), 4E-BP1(Thr37/46), p70S6K (Thr389), and the expression of LeuRS, while aerobic exercise just led to a significant increase in protein concentration and the phosphorylation of 4E-BP1(Thr37/46). Moreover, no difference was found for Sestrin2 expression between groups. The current study shows resistance exercise, but not aerobic exercise, may increase muscle protein synthesis and protein deposition, and induces muscle hypertrophy through LeuRS/mTOR signaling pathway. However, further studies are still warranted to clarify the exact effects of vary intensities and durations of aerobic exercise training.

scholarly journals Muscle Protein Synthesis is Enhanced Post-Resistance Exercise by Nutrient Stimulation of the mTOR Signaling Pathway

2007 ◽  
Vol 39 (Supplement) ◽  
pp. S82-S83
Author(s):  
Hans C. Dreyer ◽  
Micah J. Drummond ◽  
Satoshi Fujita ◽  
Erin L. Glynn ◽  
Bart Pennings ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Signaling Pathway ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mtor Signaling ◽  
Mtor Signaling Pathway ◽  
Stimulation Of

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 Essential amino acid and carbohydrate ingestion before resistance exercise does not enhance postexercise muscle protein synthesis

2009 ◽  
Vol 106 (5) ◽  
pp. 1730-1739 ◽  
Author(s):  
Satoshi Fujita ◽  
Hans C. Dreyer ◽  
Micah J. Drummond ◽  
Erin L. Glynn ◽  
Elena Volpi ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Essential Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Exercise Bout ◽  
Control Group ◽  
Carbohydrate Ingestion ◽  
Postexercise Recovery

Ingestion of an essential amino acid-carbohydrate (EAA + CHO) solution following resistance exercise enhances muscle protein synthesis during postexercise recovery. It is unclear whether EAA + CHO ingestion before resistance exercise can improve direct measures of postexercise muscle protein synthesis (fractional synthetic rate; FSR). We hypothesized that EAA + CHO ingestion before a bout of resistance exercise would prevent the exercise-induced decrease in muscle FSR and would result in an enhanced rate of muscle FSR during postexercise recovery. We studied 22 young healthy subjects before, during, and for 2 h following a bout of high-intensity leg resistance exercise. The fasting control group ( n = 11) did not ingest nutrients, and the EAA + CHO group ( n = 11) ingested a solution of EAA + CHO 1 h before beginning the exercise bout. Stable isotopic methods were used in combination with muscle biopsies to determine FSR. Immunoblotting procedures were utilized to assess cell signaling proteins associated with the regulation of FSR. We found that muscle FSR increased in the EAA + CHO group immediately following EAA + CHO ingestion ( P < 0.05), returned to basal values during exercise, and remained unchanged at 1 h postexercise. Muscle FSR decreased in the fasting group during exercise and increased at 1 h postexercise ( P < 0.05). However, the 2 h postexercise FSR increased by ∼50% in both groups with no differences between groups ( P > 0.05). Eukaryotic elongation factor 2 phosphorylation was reduced in both groups at 2 h postexercise (EAA + CHO: 39 ± 7%; fasting: 47 ± 9%; P < 0.05). We conclude that EAA + CHO ingestion before resistance exercise does not enhance postexercise FSR compared with exercise without nutrients.

scholarly journals An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise

2000 ◽  
Vol 88 (2) ◽  
pp. 386-392 ◽  
Author(s):  
Blake B. Rasmussen ◽  
Kevin D. Tipton ◽  
Sharon L. Miller ◽  
Steven E. Wolf ◽  
Robert R. Wolfe
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Venous Blood ◽  
Compartment Model ◽  
Essential Amino Acids

This study was designed to determine the response of muscle protein to the bolus ingestion of a drink containing essential amino acids and carbohydrate after resistance exercise. Six subjects (3 men, 3 women) randomly consumed a treatment drink (6 g essential amino acids, 35 g sucrose) or a flavored placebo drink 1 h or 3 h after a bout of resistance exercise on two separate occasions. We used a three-compartment model for determination of leg muscle protein kinetics. The model involves the infusion of ring-2H5-phenylalanine, femoral arterial and venous blood sampling, and muscle biopsies. Phenylalanine net balance and muscle protein synthesis were significantly increased above the predrink and corresponding placebo value ( P < 0.05) when the drink was taken 1 or 3 h after exercise but not when the placebo was ingested at 1 or 3 h. The response to the amino acid-carbohydrate drink produced similar anabolic responses at 1 and 3 h. Muscle protein breakdown did not change in response to the drink. We conclude that essential amino acids with carbohydrates stimulate muscle protein anabolism by increasing muscle protein synthesis when ingested 1 or 3 h after resistance exercise.

scholarly journals Glucocorticoid Regulates the Synthesis of Porcine Muscle Protein through m6A Modified Amino Acid Transporter SLC7A7

2022 ◽  
Vol 23 (2) ◽  
pp. 661
Author(s):  
Wei-Jing Xu ◽  
Kai Guo ◽  
Jia-Li Shi ◽  
Chang-Tong Guo ◽  
Jia-Le Xu ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Stress Response ◽  
Muscle Protein ◽  
Stress Hormones ◽  
Muscle Growth ◽  
Amino Acid Transporter ◽  
Acid Transporter ◽  
Livestock Productivity ◽  
Prolonged Stress

The occurrence of stress is unavoidable in the process of livestock production, and prolonged stress will cause the decrease of livestock productivity. The stress response is mainly regulated by the hypothalamic-pituitary-adrenal axis (HPA axis), which produces a large amount of stress hormones, namely glucocorticoids (GCs), and generates a severe impact on the energy metabolism of the animal body. It is reported that m6A modification plays an important role in the regulation of stress response and also participates in the process of muscle growth and development. In this study, we explored the effect of GCs on the protein synthesis procession of porcine skeletal muscle cells (PSCs). We prove that dexamethasone affects the expression of SLC7A7, a main amino acid transporter for protein synthesis by affecting the level of m6A modification in PSCs. In addition, we find that SLC7A7 affects the level of PSC protein synthesis by regulating the conduction of the mTOR signaling pathway, which indicates that the reduction of SLC7A7 expression may alleviate the level of protein synthesis under stress conditions.

Whey and casein labeled with l-[1-13C]leucine and muscle protein synthesis: effect of resistance exercise and protein ingestion

2011 ◽  
Vol 300 (1) ◽  
pp. E231-E242 ◽  
Author(s):  
Søren Reitelseder ◽  
Jakob Agergaard ◽  
Simon Doessing ◽  
Ida C. Helmark ◽  
Peter Lund ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Myofibrillar Protein ◽  
Western Blots ◽  
Amino Acid Availability ◽  
Amino Acid Concentrations ◽  
Myofibrillar Protein Synthesis

Muscle protein turnover following resistance exercise and amino acid availability are relatively well described. By contrast, the beneficial effects of different sources of intact proteins in relation to exercise need further investigation. Our objective was to compare muscle anabolic responses to a single bolus intake of whey or casein after performance of heavy resistance exercise. Young male individuals were randomly assigned to participate in two protein trials ( n = 9) or one control trial ( n = 8). Infusion of l-[1-13C]leucine was carried out, and either whey, casein (0.3 g/kg lean body mass), or a noncaloric control drink was ingested immediately after exercise. l-[1-13C]leucine-labeled whey and casein were used while muscle protein synthesis (MPS) was assessed. Blood and muscle tissue samples were collected to measure systemic hormone and amino acid concentrations, tracer enrichments, and myofibrillar protein synthesis. Western blots were used to investigate the Akt signaling pathway. Plasma insulin and branched-chain amino acid concentrations increased to a greater extent after ingestion of whey compared with casein. Myofibrillar protein synthesis was equally increased 1–6 h postexercise after whey and casein intake, both of which were higher compared with control ( P < 0.05). Phosphorylation of Akt and p70S6K was increased after exercise and protein intake ( P < 0.05), but no differences were observed between the types of protein except for total 4E-BP1, which was higher after whey intake than after casein intake ( P < 0.05). In conclusion, whey and casein intake immediately after resistance exercise results in an overall equal MPS response despite temporal differences in insulin and amino acid concentrations and 4E-BP1.

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