Effect of an Amino Acid, Protein, and Carbohydrate Mixture on Net Muscle Protein Balance after Resistance Exercise

2004 ◽  
Vol 14 (3) ◽  
pp. 255-271 ◽  
Author(s):  
Elisabet Børsheim ◽  
Asle Aarsland ◽  
Robert R. Wolfe

This study tests the hypotheses that (a) a mixture of whey protein, amino acids (AA), and carbohydrates (CHO) stimulates net muscle protein synthesis to a greater extent than isoenergetic CHO alone after resistance exercise; and (b) that the stimulatory effect of a protein, AA, and CHO mixture will last beyond the 1 st hour after intake. Eight subjects participated in 2 trials. In one (PAAC), they ingested 77.4 g CHO, 17.5 g whey protein, and 4.9 g AA 1 hr after resistance exercise. In the other (CON), 100 g CHO was ingested instead. They received a primed constant infusion of L-[2H5]-phenylalanine, and samples from femoral artery and vein, and biopsies from vastus lateralis were obtained. The area under the curve for net uptake of phenylalanine into muscle above pre-drink value was 128 ±42 mg • leg-1 (PAAC) versus 32 ± 10 mg - leg-1 (CON) for the 3 hr after the drink (p = .04). The net protein balance response to the mixture consisted of two components, one rapid immediate response, and a smaller delayed response about 90 min after drink, whereas in CON only a small delayed response was seen. We conclude that after resistance exercise, a mixture of whey protein, AA, and CHO stimulated muscle protein synthesis to a greater extent than isoenergetic CHO alone. Further, compared to previously reported findings, the addition of protein to an AA + CHO mixture seems to extend the anabolic effect.

2002 ◽  
Vol 283 (4) ◽  
pp. E648-E657 ◽  
Author(s):  
Elisabet Børsheim ◽  
Kevin D. Tipton ◽  
Steven E. Wolf ◽  
Robert R. Wolfe

This study tests the hypothesis that a dose of 6 g of orally administered essential amino acids (EAAs) stimulates net muscle protein balance in healthy volunteers when consumed 1 and 2 h after resistance exercise. Subjects received a primed constant infusion ofl-[2H5]phenylalanine andl-[1-13C]leucine. Samples from femoral artery and vein and biopsies from vastus lateralis were obtained. Arterial EAA concentrations increased severalfold after drinks. Net muscle protein balance (NB) increased proportionally more than arterial AA concentrations in response to drinks, and it returned rapidly to basal values when AA concentrations decreased. Area under the curve for net phenylalanine uptake above basal value was similar for the first hour after each drink (67 ± 17 vs. 77 ± 20 mg/leg, respectively). Because the NB response was double the response to two doses of a mixture of 3 g of EAA + 3 g of nonessential AA (NEAA) (14), we conclude that NEAA are not necessary for stimulation of NB and that there is a dose-dependent effect of EAA ingestion on muscle protein synthesis.


1999 ◽  
Vol 276 (4) ◽  
pp. E628-E634 ◽  
Author(s):  
Kevin D. Tipton ◽  
Arny A. Ferrando ◽  
Stuart M. Phillips ◽  
David Doyle ◽  
Robert R. Wolfe

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.


2010 ◽  
Vol 298 (2) ◽  
pp. E354-E361 ◽  
Author(s):  
Nicholas A. Burd ◽  
Jared M. Dickinson ◽  
Jennifer K. LeMoine ◽  
Chad C. Carroll ◽  
Bridget E. Sullivan ◽  
...  

Nonselective blockade of the cyclooxygenase (COX) enzymes in skeletal muscle eliminates the normal increase in muscle protein synthesis following resistance exercise. The current study tested the hypothesis that this COX-mediated increase in postexercise muscle protein synthesis is regulated specifically by the COX-2 isoform. Sixteen males (23 ± 1 yr) were randomly assigned to one of two groups that received three doses of either a selective COX-2 inhibitor (celecoxib; 200 mg/dose, 600 mg total) or a placebo in double-blind fashion during the 24 h following a single bout of knee extensor resistance exercise. At rest and 24 h postexercise, skeletal muscle protein fractional synthesis rate (FSR) was measured using a primed constant infusion of [2H5]phenylalanine coupled with muscle biopsies of the vastus lateralis, and measurements were made of mRNA and protein expression of COX-1 and COX-2. Mixed muscle protein FSR in response to exercise ( P < 0.05) was not suppressed by the COX-2 inhibitor (0.056 ± 0.004 to 0.108 ± 0.014%/h) compared with placebo (0.074 ± 0.004 to 0.091 ± 0.005%/h), nor was there any difference ( P > 0.05) between the placebo and COX-2 inhibitor postexercise when controlling for resting FSR. The COX-2 inhibitor did not influence COX-1 mRNA, COX-1 protein, or COX-2 protein levels, whereas it did increase ( P < 0.05) COX-2 mRNA (3.0 ± 0.9-fold) compared with placebo (1.3 ± 0.3-fold). It appears that the elimination of the postexercise muscle protein synthesis response by nonselective COX inhibitors is not solely due to COX-2 isoform blockade. Furthermore, the current data suggest that the COX-1 enzyme is likely the main isoform responsible for the COX-mediated increase in muscle protein synthesis following resistance exercise in humans.


2004 ◽  
Vol 96 (2) ◽  
pp. 674-678 ◽  
Author(s):  
Elisabet Børsheim ◽  
Melanie G. Cree ◽  
Kevin D. Tipton ◽  
Tabatha A. Elliott ◽  
Asle Aarsland ◽  
...  

The purpose of this study was to determine the effect of ingestion of 100 g of carbohydrates on net muscle protein balance (protein synthesis minus protein breakdown) after resistance exercise. Two groups of eight subjects performed a resistance exercise bout (10 sets of 8 repetitions of leg presses at 80% of 1-repetition maximum) before they rested in bed for 4 h. One group (CHO) received a drink consisting of 100 g of carbohydrates 1 h postexercise. The other group (Pla) received a noncaloric placebo drink. Leg amino acid metabolism was determined by infusion of 2H5- or 13C6-labeled phenylalanine, sampling from femoral artery and vein, and muscle biopsies from vastus lateralis. Drink intake did not affect arterial insulin concentration in Pla, whereas insulin increased several times after the drink in CHO ( P < 0.05 vs. Pla). Arterial phenylalanine concentration fell slightly after the drink in CHO. Net muscle protein balance between synthesis and breakdown did not change in Pla, whereas it improved in CHO from -17 ± 3 nmol·ml-1·100 ml leg-1 before drink to an average of -4 ± 4 and 0 ± 3 nmol·ml-1·100 ml leg-1 during the second and third hour after the drink, respectively ( P < 0.05 vs. Pla during last hour). The improved net balance in CHO was due primarily to a progressive decrease in muscle protein breakdown. We conclude that ingestion of carbohydrates improved net leg protein balance after resistance exercise. However, the effect was minor and delayed compared with the previously reported effect of ingestion of amino acids.


2016 ◽  
Vol 4 (15) ◽  
pp. e12893 ◽  
Author(s):  
Lindsay S. Macnaughton ◽  
Sophie L. Wardle ◽  
Oliver C. Witard ◽  
Chris McGlory ◽  
D. Lee Hamilton ◽  
...  

Author(s):  
Kirsten R. Dunlap ◽  
Jennifer L. Steiner ◽  
Michael L. Rossetti ◽  
Scot R. Kimball ◽  
Bradley S. Gordon

Muscle atrophy decreases physical function and overall health. Increased glucocorticoid production and/or use of prescription glucocorticoids can significantly induce muscle atrophy by activating the glucocorticoid receptor thereby transcribing genes that shift protein balance in favor of net protein degradation. While mechanical overload can blunt glucocorticoid-induced atrophy in young muscle, those affected by glucocorticoids generally have impaired force generation. It is unknown whether contractile force alters the ability of resistance exercise to mitigate glucocorticoid receptor translocation and induce a desirable shift in protein balance when glucocorticoids are elevated. In the present study, mice were subjected to a single bout of unilateral, electrically induced muscle contractions by stimulating the sciatic nerve at 100 Hz or 50 Hz frequencies to elicit high force or moderate force contractions of the tibialis anterior, respectively. Dexamethasone was used to activate the glucocorticoid receptor. Dexamethasone increased glucocorticoid signaling, including nuclear translocation of the receptor, but this was mitigated only by high force contractions. The ability of high force contractions to mitigate glucocorticoid receptor translocation coincided with a contraction-mediated increase in muscle protein synthesis, which did not occur in the dexamethasone treated mice subjected to moderate force contractions. Though moderate force contractions failed to increase protein synthesis following dexamethasone treatment, both high and moderate force contractions blunted the glucocorticoid-mediated increase in LC3 II:I marker of autophagy. Thus, these data show that force generation is important for the ability of resistance exercise to mitigate glucocorticoid receptor translocation and promote a desirable shift in protein balance when glucocorticoids are elevated.


2000 ◽  
Vol 278 (4) ◽  
pp. E620-E626 ◽  
Author(s):  
Debbie L. Hasten ◽  
Jina Pak-Loduca ◽  
Kathleen A. Obert ◽  
Kevin E. Yarasheski

We determined whether short-term weight-lifting exercise increases the synthesis rate of the major contractile proteins, myosin heavy chain (MHC), actin, and mixed muscle proteins in nonfrail elders and younger women and men. Fractional synthesis rates of mixed, MHC, and actin proteins were determined in seven healthy sedentary 23- to 32-yr-old and seven healthy 78- to 84-yr-old participants in paired studies done before and at the end of a 2-wk weight-lifting program. The in vivo rate of incorporation of 1-[13C]leucine into vastus lateralis MHC, actin, and mixed proteins was determined using a 14-h constant intravenous infusion of 1-[13C]leucine. Before exercise, the mixed and MHC fractional synthetic rates were lower in the older than in the younger participants ( P ≤ 0.04). Baseline actin protein synthesis rates were similar in the two groups ( P = not significant). Over a 2-wk period, participants completed ten 1- to 1.5-h weight-lifting exercise sessions: 2–3 sets per day of 9 exercises, 8–12 repetitions per set, at 60–90% of maximum voluntary muscle strength. At the end of exercise, MHC and mixed protein synthetic rates increased in the younger (88 and 121%) and older participants (105 and 182%; P < 0.001 vs. baseline). These findings indicate that MHC and mixed protein synthesis rates are reduced more than actin in advanced age. Similar to that of 23–32 yr olds, the vastus lateralis muscle in 78–84 yr olds retains the capacity to increase MHC and mixed protein synthesis rates in response to short-term resistance exercise.


2012 ◽  
Vol 113 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Cameron J. Mitchell ◽  
Tyler A. Churchward-Venne ◽  
Daniel W. D. West ◽  
Nicholas A. Burd ◽  
Leigh Breen ◽  
...  

We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 ± 1 yr, 22.6 ± 2.1 kg/m2; means ± SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant ( P < 0.01), with no difference between groups: 30%-3 = 6.8 ± 1.8%, 80%-1 = 3.2 ± 0.8%, and 80%-3= 7.2 ± 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 ( P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions ( P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation ( P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.


2007 ◽  
Vol 32 (6) ◽  
pp. 1132-1138 ◽  
Author(s):  
Jason E. Tang ◽  
Joshua J. Manolakos ◽  
Greg W. Kujbida ◽  
Paul J. Lysecki ◽  
Daniel R. Moore ◽  
...  

Whey protein is a supplemental protein source often used by athletes, particularly those aiming to gain muscle mass; however, direct evidence for its efficacy in stimulating muscle protein synthesis (MPS) is lacking. We aimed to determine the impact of consuming whey protein on skeletal muscle protein turnover in the post-exercise period. Eight healthy resistance-trained young men (age = 21 ± 1 .0 years; BMI = 26.8 ± 0.9 kg/m2 (means ± SE)) participated in a double-blind randomized crossover trial in which they performed a unilateral leg resistance exercise workout (EX: 4 sets of knee extensions and 4 sets of leg press; 8–10 repetitions/set; 80% of maximal), such that one leg was not exercised and acted as a rested (RE) comparator. After exercise, subjects consumed either an isoenergetic whey protein plus carbohydrate beverage (WHEY: 10 g protein and 21 g fructose) or a carbohydrate-only beverage (CHO: 21 g fructose and 10 g maltodextran). Subjects received pulse-tracer injections of l-[ring-2H5]phenylalanine and l-[15N]phenylalanine to measure MPS. Exercise stimulated a rise in MPS in the WHEY-EX and CHO-EX legs, which were greater than MPS in the WHEY-RE leg and the CHO-RE leg (all p < 0.05), respectively. The rate of MPS in the WHEY-EX leg was greater than in the CHO-EX leg (p < 0.001). We conclude that a small dose (10 g) of whey protein with carbohydrate (21 g) can stimulate a rise in MPS after resistance exercise in trained young men that would be supportive of a positive net protein balance, which, over time, would lead to hypertrophy.


2013 ◽  
Vol 99 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Oliver C Witard ◽  
Sarah R Jackman ◽  
Leigh Breen ◽  
Kenneth Smith ◽  
Anna Selby ◽  
...  

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