scholarly journals Effect of glucose supplement timing on protein metabolism after resistance training

1997 ◽  
Vol 82 (6) ◽  
pp. 1882-1888 ◽  
Author(s):  
B. D. Roy ◽  
M. A. Tarnopolsky ◽  
J. D. Macdougall ◽  
J. Fowles ◽  
K. E. Yarasheski
Keyword(s):  
Resistance Training ◽  
Resistance Exercise ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Vastus Lateralis ◽  
Myofibrillar Protein ◽  
Whole Body ◽  
Body Protein ◽  
Urea Excretion ◽  
Effect Of Glucose

Roy, B. D., M. A. Tarnopolsky, J. D. MacDougall, J. Fowles, and K. E. Yarasheski. Effect of glucose supplement timing on protein metabolism after resistance training. J. Appl. Physiol. 82(6): 1882–1888, 1997.—We determined the effect of the timing of glucose supplementation on fractional muscle protein synthetic rate (FSR), urinary urea excretion, and whole body and myofibrillar protein degradation after resistance exercise. Eight healthy men performed unilateral knee extensor exercise (8 sets/∼10 repetitions/∼85% of 1 single maximal repetition). They received a carbohydrate (CHO) supplement (1 g/kg) or placebo (Pl) immediately ( t = 0 h) and 1 h ( t = +1 h) postexercise. FSR was determined for exercised (Ex) and control (Con) limbs by incrementall-[1-13C]leucine enrichment into the vastus lateralis over ∼10 h postexercise. Insulin was greater ( P < 0.01) at 0.5, 0.75, 1.25, 1.5, 1.75, and 2 h, and glucose was greater ( P < 0.05) at 0.5 and 0.75 h for CHO compared with Pl condition. FSR was 36.1% greater in the CHO/Ex leg than in the CHO/Con leg ( P = not significant) and 6.3% greater in the Pl/Ex leg than in the Pl/Con leg ( P = not significant). 3-Methylhistidine excretion was lower in the CHO (110.43 ± 3.62 μmol/g creatinine) than Pl condition (120.14 ± 5.82, P < 0.05) as was urinary urea nitrogen (8.60 ± 0.66 vs. 12.28 ± 1.84 g/g creatinine, P < 0.05). This suggests that CHO supplementation (1 g/kg) immediately and 1 h after resistance exercise can decrease myofibrillar protein breakdown and urinary urea excretion, resulting in a more positive body protein balance.

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

1996 ◽  
Vol 81 (5) ◽  
pp. 2034-2038 ◽  
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.

Effect of growth hormone and resistance exercise on muscle growth in young men

1992 ◽  
Vol 262 (3) ◽  
pp. E261-E267 ◽  
Author(s):  
K. E. Yarasheski ◽  
J. A. Campbell ◽  
K. Smith ◽  
M. J. Rennie ◽  
J. O. Holloszy ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Treated Group ◽  
Whole Body ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Body Protein

The purpose of this study was to determine whether growth hormone (GH) administration enhances the muscle anabolism associated with heavy-resistance exercise. Sixteen men (21-34 yr) were assigned randomly to a resistance training plus GH group (n = 7) or to a resistance training plus placebo group (n = 9). For 12 wk, both groups trained all major muscle groups in an identical fashion while receiving 40 micrograms recombinant human GH.kg-1.day-1 or placebo. Fat-free mass (FFM) and total body water increased (P less than 0.05) in both groups but more (P less than 0.01) in the GH recipients. Whole body protein synthesis rate increased more (P less than 0.03), and whole body protein balance was greater (P = 0.01) in the GH-treated group, but quadriceps muscle protein synthesis rate, torso and limb circumferences, and muscle strength did not increase more in the GH-treated group. In the young men studied, resistance exercise with or without GH resulted in similar increments in muscle size, strength, and muscle protein synthesis, indicating that 1) the larger increase in FFM with GH treatment was probably due to an increase in lean tissue other than skeletal muscle and 2) resistance training supplemented with GH did not further enhance muscle anabolism and function.

The 1987 Borden Award Lecture.: Protein metabolism in premature human infants

1988 ◽  
Vol 66 (9) ◽  
pp. 1247-1252 ◽  
Author(s):  
Paul B. Pencharz
Keyword(s):  
Protein Synthesis ◽  
Premature Infants ◽  
Protein Metabolism ◽  
Protein Turnover ◽  
Very Low Birth Weight ◽  
Muscle Protein ◽  
Myofibrillar Protein ◽  
Whole Body ◽  
Body Protein ◽  
Positive Balance

Our studies have focused on the regulation of whole body and skeletal muscle protein metabolism in premature infants. Net deposition of protein is the result of a positive balance between protein synthesis and breakdown. To measure protein metabolism we have employed end-product studies with [15N]glycine and 13[C]leucine. Myofibrillar protein degradation was estimated by measuring the excretion of N-t-methylhistidine in urine. Energy expenditure and substrate utilization were also measured. Premature infants have high rates of protein synthesis (12 g∙kg−1∙d−1), twice those measured in children and four times those found in adults. Intrauterine malnourished babies have increased rates of protein turnover. Very low birth weight infants (< 1500 g) have higher myofibrillar protein turnover than larger babies. Intravenous feeding decreases whole body protein turnover, and we estimate visceral protein synthesis to be approximately 4 g∙kg−1∙d−1. Suboptimal energy intake worsens nitrogen utilization by reducing the reutilization of endogenous amino acids for protein synthesis. We have also examined the effects of varying the source of nonprotein energy (i.e., glucose only versus glucose plus lipid) at requirement levels and have shown there is no effect on protein metabolism. Recent improvements in technology have opened the way to detailed study of individual amino acid metabolism in neonates in the future.

scholarly journals Comprehensive assessment of post-prandial protein handling by the application of intrinsically labelled protein in vivo in human subjects

2021 ◽  
pp. 1-9
Author(s):  
Jorn Trommelen ◽  
Andrew M. Holwerda ◽  
Philippe J. M. Pinckaers ◽  
Luc J. C. van Loon
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Stable Isotope ◽  
Dietary Protein ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Human Subjects ◽  
Whole Body ◽  
Body Protein

All human tissues are in a constant state of remodelling, regulated by the balance between tissue protein synthesis and breakdown rates. It has been well-established that protein ingestion stimulates skeletal muscle and whole-body protein synthesis. Stable isotope-labelled amino acid methodologies are commonly applied to assess the various aspects of protein metabolism in vivo in human subjects. However, to achieve a more comprehensive assessment of post-prandial protein handling in vivo in human subjects, intravenous stable isotope-labelled amino acid infusions can be combined with the ingestion of intrinsically labelled protein and the collection of blood and muscle tissue samples. The combined application of ingesting intrinsically labelled protein with continuous intravenous stable isotope-labelled amino acid infusion allows the simultaneous assessment of protein digestion and amino acid absorption kinetics (e.g. release of dietary protein-derived amino acids into the circulation), whole-body protein metabolism (whole-body protein synthesis, breakdown and oxidation rates and net protein balance) and skeletal muscle metabolism (muscle protein fractional synthesis rates and dietary protein-derived amino acid incorporation into muscle protein). The purpose of this review is to provide an overview of the various aspects of post-prandial protein handling and metabolism with a focus on insights obtained from studies that have applied intrinsically labelled protein under a variety of conditions in different populations.

Resistance training reduces whole-body protein turnover and improves net protein retention in untrained young males

2006 ◽  
Vol 31 (5) ◽  
pp. 557-564 ◽  
Author(s):  
Joseph W. Hartman ◽  
Daniel R. Moore ◽  
Stuart M. Phillips
Keyword(s):  
Resistance Training ◽  
Resistance Exercise ◽  
Nitrogen Balance ◽  
Protein Turnover ◽  
Whole Body ◽  
Body Protein ◽  
Protein Retention ◽  
The Impact ◽  
Net Protein ◽  
Urinary Nitrogen

It is thought that resistance exercise results in an increased need for dietary protein; however, data also exists to support the opposite conclusion. The purpose of this study was to determine the impact of resistance exercise training on protein metabolism in novices with the hypothesis that resistance training would reduce protein turnover and improve whole-body protein retention. Healthy males (n = 8, 22 ± 1 y, BMI = 25.3 ± 1.8 kg·m–2) participated in a progressive whole-body split routine resistance-training program 5d/week for 12 weeks. Before (PRE) and after (POST) the training, oral [15N]-glycine ingestion was used to assess nitrogen flux (Q), protein synthesis (PS), protein breakdown (PB), and net protein balance (NPB = PS – PB). Macronutrient intake was controlled over a 5d period PRE and POST, while estimates of protein turnover and urinary nitrogen balance (Nbal = Nin – urine Nout) were conducted. Bench press and leg press increased 40% and 50%, respectively (p < 0.01). Fat- and bone-free mass (i.e., lean muscle mass) increased from PRE to POST (2.5 ± 0.8 kg, p < 0.05). Significant PRE to POST decreases (p <0.05) occurred in Q (0.9 ± 0.1 vs. 0.6 ± 0.1 g N·kg–1·d–1), PS (4.6 ± 0.7 vs. 2.9 ± 0.3 g·kg–1·d–1), and PB (4.3 ± 0.7 vs. 2.4 ± 0.2 g·kg–1·d–1). Significant training-induced increases in both NPB (PRE = 0.22 ± 0.13 g·kg–1·d–1; POST = 0.54 ± 0.08 g·kg–1·d–1) and urinary nitrogen balance (PRE = 2.8 ± 1.7 g N·d–1; POST = 6.5 ± 0.9 g N·d–1) were observed. A program of resistance training that induced significant muscle hypertrophy resulted in reductions of both whole-body PS and PB, but an improved NPB, which favoured the accretion of skeletal muscle protein. Urinary nitrogen balance increased after training. The reduction in PS and PB and a higher NPB in combination with an increased nitrogen balance after training suggest that dietary requirements for protein in novice resistance-trained athletes are not higher, but lower, after resistance training.

scholarly journals Basal and Postprandial Myofibrillar Protein Synthesis Rates Do Not Differ between Lean and Obese Middle-Aged Men

2019 ◽  
Vol 149 (9) ◽  
pp. 1533-1542 ◽  
Author(s):  
Imre W K Kouw ◽  
Jan Willem van Dijk ◽  
Astrid M H Horstman ◽  
Irene Fleur Kramer ◽  
Joy P B Goessens ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Myofibrillar Protein ◽  
Whole Body ◽  
Protein Digestion ◽  
Body Protein ◽  
Postprandial Period ◽  
Protein Ingestion ◽  
Myofibrillar Protein Synthesis

ABSTRACT Background Excess lipid availability has been associated with the development of anabolic resistance. As such, obesity may be accompanied by impairments in muscle protein metabolism. Objective We hypothesized that basal and postprandial muscle protein synthesis rates are lower in obese than in lean men. Methods Twelve obese men [mean ± SEM age: 48 ± 2 y; BMI (in kg/m2): 37.0 ± 1.5; body fat: 32 ± 2%] and 12 age-matched lean controls (age: 43 ± 3 y; BMI: 23.4 ± 0.4; body fat: 21 ± 1%) received primed continuous L-[ring-2H5]-phenylalanine and L-[ring-3,5-2H2]-tyrosine infusions and ingested 25 g intrinsically L-[1-13C]-phenylalanine labeled whey protein. Repeated blood and muscle samples were obtained to assess protein digestion and amino acid absorption kinetics, and basal and postprandial myofibrillar protein synthesis rates. Results Exogenous phenylalanine appearance rates increased after protein ingestion in both groups (P < 0.001), with a total of 53 ± 1% and 53 ± 2% of dietary protein–derived phenylalanine appearing in the circulation over the 5-h postprandial period in lean and obese men, respectively (P = 0.82). After protein ingestion, whole-body protein synthesis and oxidation rates increased to a greater extent in lean men than in the obese (P-interaction < 0.05), resulting in a higher whole-body protein net balance in the lean than in the obese (7.1 ± 0.2 and 4.6 ± 0.4 µmol phenylalanine · h−1 · kg−1, respectively; P-interaction < 0.001). Myofibrillar protein synthesis rates increased from 0.030 ± 0.002 and 0.028 ± 0.003%/h in the postabsorptive period to 0.034 ± 0.002 and 0.035 ± 0.003%.h−1 in the 5-h postprandial period (P = 0.03) in lean and obese men, respectively, with no differences between groups (P-interaction = 0.58). Conclusions Basal, postabsorptive myofibrillar protein synthesis rates do not differ between lean and obese middle-aged men. Postprandial protein handling, including protein digestion and amino acid absorption, and the postprandial muscle protein synthetic response after the ingestion of 25 g whey protein are not impaired in obese men. This trial was registered at www.trialregister.nl as NTR4060.

Muscle wasting in emphysema

1988 ◽  
Vol 75 (4) ◽  
pp. 415-420 ◽  
Author(s):  
W. L. Morrison ◽  
J. N. A. Gibson ◽  
C. Scrimgeour ◽  
M. J. Rennie
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Myofibrillar Protein ◽  
Whole Body ◽  
Protein Breakdown ◽  
Body Protein ◽  
Net Protein

1. We have investigated arteriovenous exchanges of tyrosine and 3-methylhistidine across leg tissue in the postabsorptive state as specific indicators of net protein balance and myofibrillar protein breakdown, respectively, in eight patients with emphysema and in 11 healthy controls. Whole-body protein turnover was measured using l-[1-13C]leucine. 2. Leg efflux of tyrosine was increased by 47% in emphysematous patients compared with normal control subjects, but 3-methylhistidine efflux was not significantly altered. 3. In emphysema, whole-body leucine flux was normal, whole-body leucine oxidation was increased, and whole-body protein synthesis was depressed. 4. These results indicate that the predominant mechanism of muscle wasting in emphysema is a fall in muscle protein synthesis, which is accompanied by an overall fall in whole-body protein turnover.

Gaining Weight: The Scientific Basis of Increasing Skeletal Muscle Mass

1999 ◽  
Vol 24 (4) ◽  
pp. 305-316 ◽  
Author(s):  
Michael E. Houston
Keyword(s):  
Protein Synthesis ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Recovery Period ◽  
Scientific Basis ◽  
Whole Body ◽  
Anabolic Hormone

Most athletes today tend to have a larger muscle mass than their predecessors. Better training and nutrition practices are responsible for much of this difference, but whatever the mechanism, the balance between muscle protein synthesis and breakdown must be in favor of increased muscle protein. Applying new techniques for measuring whole body and muscle protein synthesis to resistance exercise has led to some interesting results. In the recovery period following resistance exercise, both muscle protein synthesis and breakdown are accelerated in the fasted state. Ingestion of carbohydrate or carbohydrate and protein during recovery further increases muscle protein synthesis, due in part to an improved anabolic hormone environment. In addition, the anabolic effect of a resistance training bout may last well beyond 48 hours. Using information obtained from research studies, better training and dietary practices can optimize the benefits from resistance training, Key words: protein synthesis, protein breakdown, anabolic hormones, nutrition, resistance training

Myofibrillar protein synthesis in young and old human subjects after three months of resistance training

1995 ◽  
Vol 268 (3) ◽  
pp. E422-E427 ◽  
Author(s):  
S. Welle ◽  
C. Thornton ◽  
M. Statt
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Myofibrillar Protein ◽  
Whole Body ◽  
Synthesis Rate ◽  
Vastus Lateralis Muscle ◽  
Body Protein ◽  
Men And Women ◽  
Older Subjects ◽  
Myofibrillar Protein Synthesis

Muscle protein synthesis is slower in healthy older men and women than in young adults, but whether this results from relative disuse rather than aging is unclear. The present study was done to examine rates of myofibrillar protein synthesis before and after a 3-mo progressive resistance exercise program in young and old men and women. Protein synthesis was determined by incorporation of the tracer L-[1-13C]leucine into myofibrillar proteins obtained from the vastus lateralis muscle by needle biopsy. Before exercise, mean fractional myofibrillar synthesis was 33% slower (P < 0.01) in nine older subjects (62-72 yr old, 5 men and 4 women) than in 9 young subjects (22-31 yr old, 5 men and 4 women). Initial strength, as determined by three-repetition-maximum tests, was significantly less in the older group. Strength and training weights increased similarly in young and old groups, when expressed in relation to baseline values. Posttraining myofibrillar synthesis was determined on the day after the final training session. There was not a significant change in fractional myofibrillar synthesis in either the young or the old group after training, and the rate in the older group remained 27% slower (P < 0.05). Whole body protein turnover increased approximately 10% only in the younger group, and 24-h urinary 3-methylhistidine excretion (an index of myofibrillar proteolysis) was not significantly affected by training. These data suggest that the slower myofibrillar synthesis rate in older subjects cannot be explained by disuse.

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