scholarly journals Relationship between exercise volume and muscle protein synthesis in a rat model of resistance exercise

2017 ◽  
Vol 123 (4) ◽  
pp. 710-716 ◽  
Author(s):  
Riki Ogasawara ◽  
Yuki Arihara ◽  
Junya Takegaki ◽  
Koichi Nakazato ◽  
Naokata Ishii
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mammalian Target Of Rapamycin ◽  
High Volume ◽  
Threshold Effect ◽  
Sprague Dawley ◽  
Downstream Target ◽  
The Relationship

Resistance exercise (RE) volume is recognized as an important factor that stimulates muscle protein synthesis (MPS) and is considered, at least in part, to be involved in the mammalian target of rapamycin complex 1 (mTORC1)-associated signaling. However, the effects of relatively high-volume RE on mTORC1 and MPS remain unclear. In the present study, we used an animal model of RE to investigate the relationship between RE volume and MPS. Male Sprague-Dawley rats were subjected to RE, and muscle samples were obtained 6 h after performing 1, 3, 5, 10, or 20 sets of RE. Although 1 set of RE did not increase MPS [measured by the surface sensing of translation (SUnSET) method], multiple sets (3, 5, 10, and 20 sets) significantly increased MPS. However, the increase in MPS reached a plateau after 3 or 5 sets of RE, and no further increase in MPS was observed with additional RE sets. In contrast to the MPS response, we observed that p70S6K phosphorylation at Thr389, a marker of mTORC1 activity, and Ser240/244 phosphorylation of rpS6, a downstream target of p70S6K, gradually increased with higher RE volume. The above results suggest that the relationship between RE volume and MPS was not linear. Thus the increase in MPS with increasing RE volume saturates before p70S6K phosphorylation, suggesting a threshold effect for the relationship between p70S6K activation and MPS. NEW & NOTEWORTHY The aim of this study was to investigate the relationship between resistance exercise (RE) volume and muscle protein synthesis. We found that the relationship between RE volume and p70S6K phosphorylation was almost linear, but the increase in muscle protein synthesis began to plateau after approximately five sets of RE.

Insulin facilitation of muscle protein synthesis following resistance exercise in hindlimb-suspended rats is independent of a rapamycin-sensitive pathway

2004 ◽  
Vol 287 (6) ◽  
pp. E1070-E1075 ◽  
Author(s):  
James D. Fluckey ◽  
Esther E. Dupont-Versteegden ◽  
Micheal Knox ◽  
Dana Gaddy ◽  
Per A. Tesch ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mammalian Target Of Rapamycin ◽  
Exercise Bout ◽  
Hindlimb Suspension ◽  
Sprague Dawley

Hindlimb suspension (HS) results in rapid losses of muscle mass, which may in part be explained by attenuated rates of protein synthesis. Mammalian target of rapamycin (mTOR) regulates protein synthesis and has been implicated as a potential mediator of the muscle mass decrement with HS. This study examined the effect of resistance exercise, a muscle hypertrophy stimulant, on rates of protein synthesis after 4 days of HS in mature male Sprague-Dawley rats. Flywheel resistance exercise (2 sets × 25 repetitions) was conducted on days 2 and 4 of HS (HSRE). Sixteen hours after the last exercise bout, soleus muscles were assessed for in vitro rates of protein synthesis, with and without insulin (signaling agonist) and/or rapamycin (mTOR inhibitor). Results demonstrated that soleus mass was reduced ( P < 0.05) with HS, but this loss of mass was not observed ( P > 0.05) with HSRE. Muscle protein synthesis was diminished ( P < 0.05) with HS, with or without insulin. HSRE also had reduced rates of synthesis without insulin; however, insulin administration yielded higher ( P < 0.05) rates in HSRE compared with HS or control. Rapamycin diminished protein synthesis in all groups ( P < 0.05), but insulin rescued synthesis rates in HS and HSRE to levels similar to insulin alone for each group, suggesting that alternate signaling pathways develop to increase protein synthesis with HS. These results demonstrate that the capacity for an augmented anabolic response to resistance exercise is maintained after 4 days of HS and is independent of a rapamycin-sensitive pathway.

Resistance exercise decreases eIF2Bε phosphorylation and potentiates the feeding-induced stimulation of p70S6K1 and rpS6 in young men

2008 ◽  
Vol 295 (2) ◽  
pp. R604-R610 ◽  
Author(s):  
Elisa I. Glover ◽  
Bryan R. Oates ◽  
Jason E. Tang ◽  
Daniel R. Moore ◽  
Mark A. Tarnopolsky ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Glycogen Synthase ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mammalian Target Of Rapamycin ◽  
Young Men ◽  
Initiation Factor ◽  
Experimental Conditions ◽  
Downstream Target ◽  
Effect Of Feeding

We investigated the effect of resistance exercise and feeding on the activation of signaling proteins involved in translation initiation. Nine young men (23.7 ± 0.41 yr; BMI = 25.5 ± 1.0 kg/m2; means ± SE) were tested twice after they performed a strenuous bout of unilateral resistance exercise, such that their contralateral leg acted as a nonexercised comparator, in either the fasted and fed [1,000 kJ, each 90 min (3 doses): 10 g protein, 41 g carbohydrate, 4 g fat] states. Muscle biopsies were obtained 6 h postexercise from both legs, resulting in four experimental conditions: rest-fasted, rest-fed, exercise-fasted, and exercise-fed. Feeding increased PKB/Akt (Ser473) phosphorylation ( P < 0.05), while exercise increased the phosphorylation of Akt and the downstream 70 kDa S6 protein kinase (p70S6K1, Thr389) and ribosomal protein S6 (rpS6, Ser235/236, Ser240/244; all P < 0.05). The combination of resistance exercise and feeding increased the phosphorylation of p70S6K1 (Thr389) and rpS6 (Ser240/244) above exercise alone ( P < 0.05). Exercise also reduced phosphorylation of the catalytic epsilon subunit of eukaryotic initiation factor 2B (eIF2Bε, Ser540; P < 0.05). Mammalian target of rapamycin (mTOR, Ser2448), glycogen synthase kinase-3β (GSK-3β, Ser9), and focal adhesion kinase (FAK, Tyr576/577) phosphorylation were unaffected by either feeding or resistance exercise (all P > 0.14). In summary, feeding resulted in phosphorylation of Akt, while resistance exercise stimulated phosphorylation of Akt, p70S6K1, rpS6, and dephosphorylation eIF2Bε with a synergistic effect of feeding and exercise on p70S6K1 and its downstream target rpS6. We conclude that resistance exercise potentiates the effect of feeding on the phosphorylation and presumably activation of critical proteins involved in the regulation of muscle protein synthesis in young men.

Insulin-facilitated increase of muscle protein synthesis after resistance exercise involves a MAP kinase pathway

2006 ◽  
Vol 290 (6) ◽  
pp. E1205-E1211 ◽  
Author(s):  
James D. Fluckey ◽  
Micheal Knox ◽  
Latasha Smith ◽  
Esther E. Dupont-Versteegden ◽  
Dana Gaddy ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Signaling Pathways ◽  
Kinase Inhibitor ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Muscle Growth ◽  
Primary Component ◽  
Sprague Dawley ◽  
Sprague Dawley Rats

Recent studies have implicated the mTOR-signaling pathway as a primary component for muscle growth in mammals. The purpose of this investigation was to examine signaling pathways for muscle protein synthesis after resistance exercise. Sprague-Dawley rats (male, 6 mo old) were assigned to either resistance exercise or control groups. Resistance exercise was accomplished in operantly conditioned animals using a specially designed flywheel apparatus. Rats performed two sessions of resistance exercise, separated by 48 h, each consisting of 2 sets of 25 repetitions. Sixteen hours after the second session, animals were killed, and soleus muscles were examined for rates of protein synthesis with and without insulin and/or rapamycin (mTOR inhibitor) and/or PD-098059 (PD; MEK kinase inhibitor). Results of this study demonstrated that rates of synthesis were higher ( P < 0.05) with insulin after exercise compared with without insulin, or to control muscles, regardless of insulin. Rapamycin lowered ( P < 0.05) rates of synthesis in controls, with or without insulin, and after exercise without insulin. However, insulin was able to overcome the inhibition of rapamycin after exercise ( P < 0.05). PD had no effect on protein synthesis in control rats, but the addition of PD to exercised muscle resulted in lower ( P < 0.05) rates of synthesis, and this inhibition was not rescued by insulin. Western blot analyses demonstrated that the inhibitors used in the present study were selective and effective for preventing activation of specific signaling proteins. Together, these results suggest that the insulin-facilitated increase of muscle protein synthesis after resistance exercise requires multiple signaling pathways.

scholarly journals A comparison of 2H2O and phenylalanine flooding dose to investigate muscle protein synthesis with acute exercise in rats

2009 ◽  
Vol 297 (1) ◽  
pp. E252-E259 ◽  
Author(s):  
Heath G. Gasier ◽  
Steven E. Riechman ◽  
Michael P. Wiggs ◽  
Stephen F. Previs ◽  
James D. Fluckey
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
High Intensity ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Primary Objective ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Single Bout

The primary objective of this investigation was to determine whether 2H2O and phenylalanine (Phe) flooding dose methods yield comparable fractional rates of protein synthesis (FSR) in skeletal muscle following a single bout of high-intensity resistance exercise (RE). Sprague-Dawley rats were assigned by body mass to either 4-h control (CON 4 h; n = 6), 4-h resistance exercise (RE 4 h; n = 6), 24-h control (CON 24 h; n = 6), or 24-h resistance exercise (RE 24 h; n = 6). The RE groups were operantly conditioned to engage in a single bout of high-intensity, “squat-like” RE. All rats were given an intraperitoneal injection of 99.9% 2H2O and provided 4.0% 2H2O drinking water for either 24 ( n = 12) or 4 h ( n = 12) prior to receiving a flooding dose of l-[2,3,4,5,6-3H]Phe 16 h post-RE. Neither method detected an effect of RE on FSR in the mixed gastrocnemius, plantaris, or soleus muscle. Aside from the qualitative similarities between methods, the 4-h 2H2O FSR measurements, when expressed in percent per hour, were quantitatively greater than the 24-h 2H2O and Phe flooding in all muscles ( P < 0.001), and the 24-h 2H2O was greater than the Phe flooding dose in the mixed gastrocnemius and plantaris ( P < 0.05). In contrast, the actual percentage of newly synthesized protein was significantly higher in the 24- vs. 4-h 2H2O and Phe flooding dose groups ( P < 0.001). These results suggest that the methodologies provide “qualitatively” similar results when a perturbation such as RE is studied. However, due to potential quantitative differences between methods, the experimental question should determine what approach should be used.

scholarly journals Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle

2008 ◽  
Vol 294 (2) ◽  
pp. E392-E400 ◽  
Author(s):  
Hans C. Dreyer ◽  
Micah J. Drummond ◽  
Bart Pennings ◽  
Satoshi Fujita ◽  
Erin L. Glynn ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mammalian Target Of Rapamycin ◽  
Essential Amino Acids ◽  
Mtor Signaling ◽  
Control Group ◽  
Carbohydrate Ingestion ◽  
Akt Phosphorylation

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.

scholarly journals Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men

PLoS ONE ◽  
2010 ◽  
Vol 5 (8) ◽  
pp. e12033 ◽  
Author(s):  
Nicholas A. Burd ◽  
Daniel W. D. West ◽  
Aaron W. Staples ◽  
Philip J. Atherton ◽  
Jeff M. Baker ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Young Men ◽  
High Volume ◽  
High Load ◽  
Low Load ◽  
Volume Resistance ◽  
Low Volume

scholarly journals Leucine or carbohydrate supplementation reduces AMPK and eEF2 phosphorylation and extends postprandial muscle protein synthesis in rats

2011 ◽  
Vol 301 (6) ◽  
pp. E1236-E1242 ◽  
Author(s):  
Gabriel J. Wilson ◽  
Donald K. Layman ◽  
Christopher J. Moulton ◽  
Layne E. Norton ◽  
Tracy G. Anthony ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Test Meal ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Adenosine Monophosphate ◽  
Energy Status ◽  
Sprague Dawley ◽  
Translation Elongation ◽  
Cellular Energy ◽  
Mtorc1 Signaling

Muscle protein synthesis (MPS) increases after consumption of a protein-containing meal but returns to baseline values within 3 h despite continued elevations of plasma amino acids and mammalian target of rapamycin (mTORC1) signaling. This study evaluated the potential for supplemental leucine (Leu), carbohydrates (CHO), or both to prolong elevated MPS after a meal. Male Sprague-Dawley rats (∼270 g) trained to consume three meals daily were food deprived for 12 h, and then blood and gastrocnemius muscle were collected 0, 90, or 180 min after a standard 4-g test meal (20% whey protein). At 135 min postmeal, rats were orally administered 2.63 g of CHO, 270 mg of Leu, both, or water (sham control). Following test meal consumption, MPS peaked at 90 min and then returned to basal ( time 0) rates at 180 min, although ribosomal protein S6 kinase and eIF4E-binding protein-1 phosphorylation remained elevated. In contrast, rats administered Leu and/or CHO supplements at 135 min postmeal maintained peak MPS through 180 min. MPS was inversely associated with the phosphorylation states of translation elongation factor 2, the “cellular energy sensor” adenosine monophosphate-activated protein kinase-α (AMPKα) and its substrate acetyl-CoA carboxylase, and increases in the ratio of AMP/ATP. We conclude that the incongruity between MPS and mTORC1 at 180 min reflects a block in translation elongation due to reduced cellular energy. Administering Leu or CHO supplements ∼2 h after a meal maintains cellular energy status and extends the postprandial duration of MPS.

scholarly journals The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein

2016 ◽  
Vol 4 (15) ◽  
pp. e12893 ◽  
Author(s):  
Lindsay S. Macnaughton ◽  
Sophie L. Wardle ◽  
Oliver C. Witard ◽  
Chris McGlory ◽  
D. Lee Hamilton ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Whey Protein ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Body Resistance

scholarly journals Resistance exercise maintains skeletal muscle protein synthesis during bed rest

1997 ◽  
Vol 82 (3) ◽  
pp. 807-810 ◽  
Author(s):  
Arny A. Ferrando ◽  
Kevin D. Tipton ◽  
Marcas M. Bamman ◽  
Robert R. Wolfe
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Lean Body Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Bed Rest ◽  
Skeletal Muscle Protein ◽  
Skeletal Muscle Protein Synthesis

Ferrando, Arny A., Kevin D. Tipton, Marcas M. Bamman, and Robert R. Wolfe. Resistance exercise maintains skeletal muscle protein synthesis during bed rest. J. Appl. Physiol. 82(3): 807–810, 1997.—Spaceflight results in a loss of lean body mass and muscular strength. A ground-based model for microgravity, bed rest, results in a loss of lean body mass due to a decrease in muscle protein synthesis (MPS). Resistance training is suggested as a proposed countermeasure for spaceflight-induced atrophy because it is known to increase both MPS and skeletal muscle strength. We therefore hypothesized that scheduled resistance training throughout bed rest would ameliorate the decrease in MPS. Two groups of healthy volunteers were studied during 14 days of simulated microgravity. One group adhered to strict bed rest (BR; n = 5), whereas a second group engaged in leg resistance exercise every other day throughout bed rest (BREx; n = 6). MPS was determined directly by the incorporation of infusedl-[ ring-13C6]phenylalanine into vastus lateralis protein. After 14 days of bed rest, MPS in the BREx group did not change and was significantly greater than in the BR group. Thus moderate-resistance exercise can counteract the decrease in MPS during bed rest.

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