Sex-based comparisons of myofibrillar protein synthesis after resistance exercise in the fed state

We made sex-based comparisons of rates of myofibrillar protein synthesis (MPS) and anabolic signaling after a single bout of high-intensity resistance exercise. Eight men (20 ± 10 yr, BMI = 24.3 ± 2.4) and eight women (22 ± 1.8 yr, BMI = 23.0 ± 1.9) underwent primed constant infusions of l-[ ring-13C6]phenylalanine on consecutive days with serial muscle biopsies. Biopsies were taken from the vastus lateralis at rest and 1, 3, 5, 24, 26, and 28 h after exercise. Twenty-five grams of whey protein was ingested immediately and 26 h after exercise. We also measured exercise-induced serum testosterone because it is purported to contribute to increases in myofibrillar protein synthesis (MPS) postexercise and its absence has been hypothesized to attenuate adaptative responses to resistance exercise in women. The exercise-induced area under the testosterone curve was 45-fold greater in men than women in the early (1 h) recovery period following exercise ( P < 0.001). MPS was elevated similarly in men and women (2.3- and 2.7-fold, respectively) 1–5 h postexercise and after protein ingestion following 24 h recovery. Phosphorylation of mTORSer2448 was elevated to a greater extent in men than women acutely after exercise ( P = 0.003), whereas increased phosphorylation of p70S6K1Thr389 was not different between sexes. Androgen receptor content was greater in men (main effect for sex, P = 0.049). Atrogin-1 mRNA abundance was decreased after 5 h recovery in both men and women ( P < 0.001), and MuRF-1 expression was elevated in men after protein ingestion following 24 h recovery ( P = 0.003). These results demonstrate minor sex-based differences in signaling responses and no difference in the MPS response to resistance exercise in the fed state. Interestingly, our data demonstrate that exercise-induced increases in MPS are dissociated from postexercise testosteronemia and that stimulation of MPS occurs effectively with low systemic testosterone concentrations in women.

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Short inter-set rest blunts resistance exercise-induced increases in myofibrillar protein synthesis and intracellular signalling in young males

Experimental Physiology ◽

10.1113/ep085647 ◽

2016 ◽

Vol 101 (7) ◽

pp. 866-882 ◽

Cited By ~ 30

Author(s):

James McKendry ◽

Alberto Pérez-López ◽

Michael McLeod ◽

Dan Luo ◽

Jessica R. Dent ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Exercise ◽

Myofibrillar Protein ◽

Intracellular Signalling ◽

Young Males ◽

Exercise Induced ◽

Myofibrillar Protein Synthesis

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Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis

The Journal of Physiology ◽

10.1113/jphysiol.2012.244897 ◽

2013 ◽

Vol 591 (9) ◽

pp. 2319-2331 ◽

Cited By ~ 217

Author(s):

José L. Areta ◽

Louise M. Burke ◽

Megan L. Ross ◽

Donny M. Camera ◽

Daniel W. D. West ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Exercise ◽

Myofibrillar Protein ◽

Protein Ingestion ◽

Prolonged Recovery ◽

Myofibrillar Protein Synthesis

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Presleep dietary protein-derived amino acids are incorporated in myofibrillar protein during postexercise overnight recovery

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00273.2016 ◽

2018 ◽

Vol 314 (5) ◽

pp. E457-E467 ◽

Cited By ~ 33

Author(s):

Jorn Trommelen ◽

Imre W. K. Kouw ◽

Andrew M. Holwerda ◽

Tim Snijders ◽

Shona L. Halson ◽

...

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Dietary Protein ◽

Myofibrillar Protein ◽

Whole Body ◽

Body Protein ◽

Protein Ingestion ◽

Casein Protein ◽

The Impact ◽

Myofibrillar Protein Synthesis

The purpose of this study was to determine the impact of ingesting 30 g casein protein with and without 2 g free leucine before sleep on myofibrillar protein synthesis rates during postexercise overnight recovery. Thirty-six healthy young men performed a single bout of resistance-type exercise in the evening (1945) after a full day of dietary standardization. Thirty minutes before sleep (2330), subjects ingested 30 g intrinsically l-[1-13C]phenylalanine-labeled protein with (PRO+leu, n = 12) or without (PRO, n = 12) 2 g free leucine, or a noncaloric placebo (PLA, n = 12). Continuous intravenous l-[ ring-2H5]phenylalanine, l-[1-13C]leucine, and l-[ ring-2H2]tyrosine infusions were applied. Blood and muscle tissue samples were collected to assess whole body protein net balance, myofibrillar protein synthesis rates, and overnight incorporation of dietary protein-derived amino acids into myofibrillar protein. Protein ingestion before sleep improved overnight whole body protein net balance ( P < 0.001). Myofibrillar protein synthesis rates did not differ significantly between treatments as assessed by l-[ ring-2H5]phenylalanine (0.057 ± 0.002, 0.055 ± 0.002, and 0.055 ± 0.004%/h for PLA, PRO, and PRO+leu, respectively; means ± SE; P = 0.850) or l-[1-13C]leucine (0.080 ± 0.004, 0.073 ± 0.004, and 0.083 ± 0.006%/h, respectively; P = 0.328). Myofibrillar l-[1-13C]phenylalanine enrichments increased following protein ingestion but did not differ between the PRO and PRO+leu treatments. In conclusion, protein ingestion before sleep improves whole body protein net balance and provides amino acids that are incorporated into myofibrillar protein during sleep. However, the ingestion of 30 g casein protein with or without additional free leucine before sleep does not increase muscle protein synthesis rates during postexercise overnight recovery.

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Hypoenergetic diet-induced reductions in myofibrillar protein synthesis are restored with resistance training and balanced daily protein ingestion in older men

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00550.2014 ◽

2015 ◽

Vol 308 (9) ◽

pp. E734-E743 ◽

Cited By ~ 58

Author(s):

Caoileann H. Murphy ◽

Tyler A. Churchward-Venne ◽

Cameron J. Mitchell ◽

Nathan M. Kolar ◽

Amira Kassis ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Training ◽

Older Men ◽

Myofibrillar Protein ◽

Energy Restriction ◽

Protein Distribution ◽

Protein Meal ◽

Fed State ◽

Sarcoplasmic Protein ◽

Myofibrillar Protein Synthesis

Strategies to enhance weight loss with a high fat-to-lean ratio in overweight/obese older adults are important since lean loss could exacerbate sarcopenia. We examined how dietary protein distribution affected muscle protein synthesis during energy balance (EB), energy restriction (ER), and energy restriction plus resistance training (ER + RT). A 4-wk ER diet was provided to overweight/obese older men (66 ± 4 yr, 31 ± 5 kg/m2) who were randomized to either a balanced (BAL: 25% daily protein/meal × 4) or skewed (SKEW: 7:17:72:4% daily protein/meal; n = 10/group) pattern. Myofibrillar and sarcoplasmic protein fractional synthetic rates (FSR) were measured during a 13-h primed continuous infusion of l-[ ring-13C6]phenylalanine with BAL and SKEW pattern of protein intake in EB, after 2 wk ER, and after 2 wk ER + RT. Fed-state myofibrillar FSR was lower in ER than EB in both groups ( P < 0.001), but was greater in BAL than SKEW ( P = 0.014). In ER + RT, fed-state myofibrillar FSR increased above ER in both groups and in BAL was not different from EB ( P = 0.903). In SKEW myofibrillar FSR remained lower than EB ( P = 0.002) and lower than BAL ( P = 0.006). Fed-state sarcoplasmic protein FSR was reduced similarly in ER and ER + RT compared with EB ( P < 0.01) in both groups. During ER in overweight/obese older men a BAL consumption of protein stimulated the synthesis of muscle contractile proteins more effectively than traditional, SKEW distribution. Combining RT with a BAL protein distribution “rescued” the lower rates of myofibrillar protein synthesis during moderate ER.

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Rapid aminoacidemia enhances myofibrillar protein synthesis and anabolic intramuscular signaling responses after resistance exercise

American Journal of Clinical Nutrition ◽

10.3945/ajcn.111.013722 ◽

2011 ◽

Vol 94 (3) ◽

pp. 795-803 ◽

Cited By ~ 154

Author(s):

D. W. West ◽

N. A. Burd ◽

V. G. Coffey ◽

S. K. Baker ◽

L. M. Burke ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Exercise ◽

Myofibrillar Protein ◽

Myofibrillar Protein Synthesis

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Altered anabolic signalling and reduced stimulation of myofibrillar protein synthesis after feeding and resistance exercise in people with obesity

The Journal of Physiology ◽

10.1113/jp276210 ◽

2018 ◽

Vol 596 (21) ◽

pp. 5119-5133 ◽

Cited By ~ 12

Author(s):

Joseph W. Beals ◽

Sarah K. Skinner ◽

Colleen F. McKenna ◽

Elizabeth G. Poozhikunnel ◽

Samee A. Farooqi ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Exercise ◽

Myofibrillar Protein ◽

Anabolic Signalling ◽

Myofibrillar Protein Synthesis ◽

Stimulation Of

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Damaging eccentric exercise attenuates disuse induced declines in daily myofibrillar protein synthesis and transiently prevents muscle atrophy in healthy men.

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00294.2021 ◽

2021 ◽

Author(s):

Tom S. O. Jameson ◽

Sean P Kilroe ◽

Jonathan Fulford ◽

Doaa Reda Abdelrahman ◽

Andrew John Murton ◽

...

Keyword(s):

Protein Synthesis ◽

Eccentric Exercise ◽

Vastus Lateralis ◽

Quadriceps Muscle ◽

Quadriceps Strength ◽

Myofibrillar Protein ◽

Muscle Volume ◽

Vastus Lateralis Muscle ◽

Deuterated Water ◽

Myofibrillar Protein Synthesis

Introduction: Short-term disuse leads to muscle loss driven by lowered daily myofibrillar protein synthesis (MyoPS). However, disuse commonly results from muscle damage, and its influence on muscle deconditioning during disuse is unknown. Methods: 21 males (20±1 y, BMI=24±1 kg·m-2 (±SEM)) underwent 7 days of unilateral leg immobilization immediately preceded by 300 bilateral, maximal, muscle-damaging eccentric quadriceps contractions (DAM; n=10) or no exercise (CON; n=11). Participants ingested deuterated water and underwent temporal bilateral thigh MRI scans and vastus lateralis muscle biopsies of immobilized (IMM) and non-immobilized (N-IMM) legs. Results: N-IMM quadriceps muscle volume remained unchanged throughout in both groups. IMM quadriceps muscle volume declined after 2 days by 1.7±0.5% in CON (P=0.031; and by 1.3±0.6% when corrected to N-IMM; P=0.06) but did not change in DAM, and declined equivalently in CON (by 6.4±1.1% [5.0±1.6% when corrected to N-IMM]) and DAM (by 2.6±1.8% [4.0±1.9% when corrected to N-IMM]) after 7 days. Immobilization began to decrease MyoPS compared with N-IMM in both groups after 2 days (P=0.109), albeit with higher MyoPS rates in DAM compared with CON (P=0.035). Frank suppression of MyoPS was observed between days 2-7 in CON (IMM=1.04±0.12, N-IMM=1.86±0.10%·d-1; P=0.002) but not DAM (IMM=1.49±0.29, N-IMM=1.90±0.30%·d-1; P>0.05). Declines in MyoPS and quadriceps volume after 7 days correlated positively in CON (R2=0.403; P=0.035) but negatively in DAM (R2=0.483; P=0.037). Quadriceps strength declined following immobilization in both groups, but to a greater extent in DAM. Conclusion: Prior muscle damaging eccentric exercise increases MyoPS and prevents loss of quadriceps muscle volume after 2 (but not 7) days of disuse.

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