Resistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in men (original) (raw)
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Amino Acids, 2009
The effects of timed ingestion of high-quality protein before and after resistance exercise are not well known. In this study, young men were randomized to protein (n = 11), placebo (n = 10) and control (n = 10) groups. Muscle cross-sectional area by MRI and muscle forces were analyzed before and after 21 weeks of either heavy resistance training (RT) or control period. Muscle biopsies were taken before, and 1 and 48 h after 5 9 10 repetition leg press exercise (RE) as well as 21 weeks after RT. Protein (15 g of whey both before and after exercise) or non-energetic placebo were provided to subjects in the context of both single RE bout (acute responses) as well as each RE workout twice a week throughout the 21-week-RT. Protein intake increased (P B 0.05) RT-induced muscle cross-sectional area enlargement and cell-cycle kinase cdk2 mRNA expression in the vastus lateralis muscle suggesting higher proliferating cell activation response with protein supplementation. Moreover, protein intake seemed to prevent 1 h post-RE decrease in myostatin and myogenin mRNA expression but did not affect activin receptor IIb, p21, FLRG, MAFbx or MyoD expression. In conclusion, protein intake close to resistance exercise workout may alter mRNA expression in a manner advantageous for muscle hypertrophy.
Nutrients, 2009
The effect of resistance exercise with the ingestion of supplementary protein on the activation of the mTOR cascade, in human skeletal muscle has not been fully elucidated. In this study, the impact of a single bout of resistance exercise, immediately followed by a single dose of whey protein isolate (WPI) or placebo supplement, on the activation of mTOR signalling was analyzed. Young untrained men completed a maximal single-legged knee extension exercise bout and were randomized to ingest either WPI supplement (n = 7) or the placebo (n = 7). Muscle biopsies were taken from the vastus lateralis before, and 2, 4 and 24 hr post-exercise. WPI or placebo ingestion consumed immediately post-exercise had no impact on the phosphorylation of Akt (Ser 473 ). However, WPI significantly enhanced phosphorylation of mTOR (Ser 2448 ), 4E-BP1 (Thr 37/46 ) and p70 S6K (Thr 389 ) at 2 hr post-exercise. This study demonstrates that a single dose of WPI, when consumed in modest quantities, taken immediately after resistance exercise elicits an acute and transient activation of translation initiation within the exercised skeletal muscle.
Synergistic effects of resistance training and protein intake: Practical aspects
Nutrition (Burbank, Los Angeles County, Calif.), 2014
the effects of different protein sources and timing protocols on MPS. The sum of the adaptions from 43 each individual training session are essential to muscle hypertrophy, and thus highlight the 44 importance of an optimal supplementation protocol. The purpose of this review is to present recent 45 findings reported in the literature and discuss the practical application of these results. In that light, 46 new speculations and questions will arise that may direct future investigations. The information and 47 recommendations generated in this review will thereby benefit practicing sport and clinical 48 nutritionists alike. 49 50 51 52 53 54 55 56 57 M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 supplementation to promote muscle protein synthesis (MPS)? Next, what is the effect of varying 79 sources of protein on muscle mass, and how does the amino acid and leucine compositions of these 80 proteins affect MPS? Finally, for healthy and elderly subjects engaged in resistance training, what 81 are the effects of pulse versus bolus supplementation schedules on MPS and glucose homeostasis? 82 100 following EAA and leucine intake in the resting state [13]. Thus, the interaction between resistance 101 training and EAA ingestion is synergistic: overload likely activates the machinery required for MPS; 102 however, increased synthesis, and therefore new muscle protein, will not begin until amino academia 103 occurs. While an acute bout of resistance training and amino acid intake is capable of inducing MPS, 104 the practical applications to these results are limited as it requires chronic overload over successive 105 sessions for MPS to manifest in measurable hypertrophy. Although chronic resistance training 106 appears to reduce the ability of overload to signal the mammalian target of rapamyacin (mTOR) [14], 128 to resistance exercise [23]. Given that a minimal of 6 weeks of training and supplementation are 129 required for measurable increases in muscle cross sectional area to occur [24], only training studies 130 that included a resistance weight-lifting protocol, were at least 6 weeks in length, and contained at 131 least two training sessions per week are included in this section of the review.
Journal of the International Society of Sports Nutrition, 2011
Background This study examined the effects of a whey protein supplement in conjunction with an acute bout of lower body resistance exercise, in recreationally-active males, on serum insulin and insulin like growth factor 1 (IGF-1) and Akt/mTOR signaling markers indicative of muscle protein synthesis: insulin receptor substrate 1 (IRS-1), AKT, mammalian target of rapamycin (mTOR), p70S6 kinase (p70S6K) and 4E-binding protein 1 (4E-BP1). Methods In a randomized, double-blind, cross-over design, 10 males ingested 1 week apart, either 10 g of whey protein (5.25 g EAAs) or carbohydrate (maltodextrose), 30 min prior to a lower-body resistance exercise bout. The resistance exercise bout consisted of 4 sets of 8-10 reps at 80% of the one repetition maximum (RM) on the angled leg press and knee extension exercises. Blood and muscle samples were obtained prior to, and 30 min following supplement ingestion and 15 min and 120 min post-exercise. Serum and muscle data were analyzed using two-way ...
Nutrition Research, 2015
The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway appears to be the primary regulator of muscle protein synthesis. A variety of stimuli including resistance exercise, amino acids, and hormonal signals activate mTORC1 signaling. The purpose of this study was to investigate the effect of a protein supplement on mTORC1 signaling following a resistance exercise protocol designed to promote elevations in circulating hormone concentrations. We hypothesized that the protein supplement would augment the intramuscular anabolic signaling response. Ten resistancetrained men (age, 24.7 ± 3.4 years; weight, 90.1 ± 11.3 kg; height, 176.0 ± 4.9 cm) received either a placebo or a supplement containing 20 g protein, 6 g carbohydrates, and 1 g fat after high-volume, short-rest lower-body resistance exercise. Blood samples were obtained at baseline, immediately, 30 minutes, 1 hour, 2 hours, and 5 hours after exercise. Fine-needle muscle biopsies were completed at baseline, 1 hour, and 5 hours after exercise. Myoglobin, lactate dehydrogenase, and lactate concentrations were significantly elevated after resistance exercise (P < .0001); however, no differences were observed between trials.
European Journal of Applied Physiology, 2007
Myostatin decreases muscle mass and this is accomplished, in part, by inhibiting muscle satellite cell proliferation and diVerentiation by regulating the expression of cell cycle-related proteins (e.g. p21 and cdk2) and myogenic regulatory factors (e.g. myogenin and MyoD). The purpose of this investigation was to determine whether protein ingestion before and after a resistance exercise (RE) bout aVects myostatin and cell cycle-related gene expression. Strength-trained middle-aged to older men were divided into a protein group (61.4 § 4.3 years, n = 9) or a placebo group (62.1 § 4.2 years, n = 9). Muscle biopsies from the vastus lateralis muscle were taken at rest and 1 and 48 h after a 5 £ 10 repetition leg press RE bout. Protein (15 g whey) or non-caloric placebo was taken immediately before and after the RE bout. mRNA expression levels of myostatin and related genes (AcvrIIb, FLRG, p21, p27, cdk2, myogenin and MyoD) were determined by Taqman probe-based real-time RT-PCR and normalized to GAPDH mRNA. Myostatin mRNA decreased after a RE bout, but only in the placebo group (P · 0.05). Conversely, myosta-tin-binding protein FLRG and cell-cycle kinase cdk2 mRNA increased only in the protein group (P · 0.05). p21 mRNA was increased at 1 h post-RE in placebo (P · 0.05) and tended to be increased in the protein group (P = 0.08). Myostatin, its binding protein and cell cycle-related gene expressions are aVected by single RE bout and these responses are further modiWed by whey protein intake. Therefore, controlling nutrition intake is important when studying gene expression responses to exercise.
Physiological Reports, 2016
The currently accepted amount of protein required to achieve maximal stimulation of myofibrillar protein synthesis (MPS) following resistance exercise is 20-25 g. However, the influence of lean body mass (LBM) on the response of MPS to protein ingestion is unclear. Our aim was to assess the influence of LBM, both total and the amount activated during exercise, on the maximal response of MPS to ingestion of 20 or 40 g of whey protein following a bout of whole-body resistance exercise. Resistance-trained males were assigned to a group with lower LBM (≤65 kg; LLBM n = 15) or higher LBM (≥70 kg; HLBM n = 15) and participated in two trials in random order. MPS was measured with the infusion of 13 C 6-phenylalanine tracer and collection of muscle biopsies following ingestion of either 20 or 40 g protein during recovery from a single bout of whole-body resistance exercise. A similar response of MPS during exercise recovery was observed between LBM groups following protein ingestion (20 g-LLBM: 0.048 AE 0.018%Áh À1 ; HLBM: 0.051 AE 0.014%Áh À1 ; 40 g-LLBM: 0.059 AE 0.021%Áh À1 ; HLBM: 0.059 AE 0.012%Áh À1). Overall (groups combined), MPS was stimulated to a greater extent following ingestion of 40 g (0.059 AE 0.020%Áh À1) compared with 20 g (0.049 AE 0.020%Áh À1 ; P = 0.005) of protein. Our data indicate that ingestion of 40 g whey protein following whole-body resistance exercise stimulates a greater MPS response than 20 g in young resistance-trained men. However, with the current doses, the total amount of LBM does not seem to influence the response.
Sports Medicine, 2015
Muscle protein synthesis (MPS) is stimulated by resistance exercise (RE) and is further stimulated by protein ingestion. The summation of periods of RE-induced increases in MPS can induce hypertrophy chronically. As such, studying the response of MPS with resistance training (RT) is informative, as adaptations in this process can modulate muscle mass gain. Previous studies have shown that the amplitude and duration of increases in MPS after an acute bout of RE are modulated by an individual's training status. Nevertheless, it has been shown that the initial responses of MPS to RE and nutrition are not correlated with subsequent hypertrophy. Thus, early acute responses of MPS in the hours after RE, in an untrained state, do not capture how MPS can affect RE-induced muscle hypertrophy. The purpose of this review is provide an in-depth understanding of the dynamic process of muscle hypertrophy throughout RT by examining all of the available data on MPS after RE and in different phases of an RT programme. Analysis of the time course and the overall response of MPS is critical to determine the potential protein accretion after an RE bout. Exercise-induced increases in MPS are shorter lived and peak earlier in the trained state than in the untrained state, resulting in a smaller overall muscle protein synthetic response in the trained state. Thus, RT induces a dampening of the MPS response, potentially limiting protein accretion, but when this occurs remains unknown.
Nutrition Research, 2014
The effects of a single bout of resistance exercise (RE) in conjunction with peri-exercise branched chain amino acid (BCAA) and carbohydrate (CHO) ingestion on skeletal muscle signaling markers indicative of muscle protein synthesis (MPS) were determined. It was hypothesized that CHO + BCAA would elicit a more profound effect on these signaling markers compared to CHO. Twenty-seven males were randomly assigned to CHO, CHO + BCAA, or placebo (PLC) groups. Four sets of leg presses and leg extensions were performed at 80% 1RM. Supplements were ingested 30 min and immediately prior to and after RE. Venous blood and muscle biopsy samples were obtained immediately prior to supplement ingestion and 0.5 hr, 2 hr, and 6 hr after RE. Serum insulin and glucose and phosphorylated levels of muscle insulin receptor substrate 1 (IRS1), protein kinase B (Akt), mammalian target of rapamycin (mTOR), p70S6 kinase (p70S6K), and 4E binding protein 1 (4E-BP1) were assessed. Data were analyzed by two-way repeated measures ANOVA. Significant group x time interactions were observed for glucose and insulin (p < 0.05) showing that CHO and CHO + BCAA were significantly greater than PLC. Significant time main effects were observed for IRS1 (p = 0.001), Akt (p = 0.031), mTOR (p = 0.003), and p70S6K (p = 0.001). CHO and CHO + BCAA supplementation significantly increased IRS-1 compared to PLC (p = 0.002). However, peri-exercise co-ingestion of CHO and BCAA did not augment RE-induced increases in skeletal muscle signaling markers indicative of MPS when compared to CHO.
The Journal of Physiology, 2013
• A single bolus of ∼20 g of protein after a bout of resistance exercise provides a maximal anabolic stimulus during the early post-exercise recovery period (∼5 h), but the effect of various protein feeding strategies on skeletal muscle protein synthesis during an extended recovery period (12 h) is unknown. • We compared three different patterns of ingestion of 80 g of protein during 12 h recovery after resistance exercise and the associated anabolic response in human skeletal muscle. Protein was ingested in 10, 20 or 40 g feedings using a pulsed, intermediate or bolus ingestion regimen, respectively. • Our results indicate that repeated ingestion of 20 g of protein was superior for stimulating muscle protein synthesis during the 12 h experimental period. • The three dietary treatments induced differential phosphorylation of signalling proteins and changes in mRNA abundance. • This study shows that the distribution of protein intake is an important variable to promote attainment and maintenance of peak muscle mass.