Age and aerobic exercise training effects on whole body and muscle protein metabolism

2004 ◽  
Vol 286 (1) ◽  
pp. E92-E101 ◽  
Author(s):  
Kevin R. Short ◽  
Janet L. Vittone ◽  
Maureen L. Bigelow ◽  
David N. Proctor ◽  
K. Sreekumaran Nair
Keyword(s):  
Protein Synthesis ◽  
Exercise Training ◽  
Protein Metabolism ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Fat Free Mass ◽  
Whole Body ◽  
Men And Women ◽  
Muscle Protein Metabolism

Aging in humans is associated with loss of lean body mass, but the causes are incompletely defined. Lean tissue mass and function depend on continuous rebuilding of proteins. We tested the hypotheses that whole body and mixed muscle protein metabolism declines with age in men and women and that aerobic exercise training would partly reverse this decline. Seventy-eight healthy, previously untrained men and women aged 19-87 yr were studied before and after 4 mo of bicycle training (up to 45 min at 80% peak heart rate, 3-4 days/wk) or control (flexibility) activity. At the whole body level, protein breakdown (measured as [13C]leucine and [15N]phenylalanine flux), Leu oxidation, and protein synthesis (nonoxidative Leu disposal) declined with age at a rate of 4-5% per decade ( P < 0.001). Fat-free mass was closely correlated with protein turnover and declined 3% per decade ( P < 0.001), but even after covariate adjustment for fat-free mass, the decline in protein turnover with age remained significant. There were no differences between men and women after adjustment for fat-free mass. Mixed muscle protein synthesis also declined with age 3.5% per decade ( P < 0.05). Exercise training improved aerobic capacity 9% overall ( P < 0.01), and mixed muscle protein synthesis increased 22% ( P < 0.05), with no effect of age on the training response for either variable. Fat-free mass, whole body protein turnover, and resting metabolic rate were unchanged by training. We conclude that rates of whole body and muscle protein metabolism decline with age in men and women, thus indicating that there is a progressive decline in the body's remodeling processes with aging. This study also demonstrates that aerobic exercise can enhance muscle protein synthesis irrespective of age.

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.

Effects of acute creatine monohydrate supplementation on leucine kinetics and mixed-muscle protein synthesis

2001 ◽  
Vol 91 (3) ◽  
pp. 1041-1047 ◽  
Author(s):  
G. Parise ◽  
S. Mihic ◽  
D. MacLennan ◽  
K. E. Yarasheski ◽  
M. A. Tarnopolsky
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Fat Free Mass ◽  
Whole Body ◽  
Synthetic Rate ◽  
Fractional Synthetic Rate ◽  
Before And After ◽  
Total Creatine ◽  
Plasma Leucine

Creatine monohydrate (CrM) supplementation during resistance exercise training results in a greater increase in strength and fat-free mass than placebo. Whether this is solely due to an increase in intracellular water or whether there may be alterations in protein turnover is not clear at this point. We examined the effects of CrM supplementation on indexes of protein metabolism in young healthy men ( n = 13) and women ( n = 14). Subjects were randomly allocated to CrM (20 g/day for 5 days followed by 5 g/day for 3–4 days) or placebo (glucose polymers) and tested before and after the supplementation period under rigorous dietary and exercise controls. Muscle phosphocreatine, creatine, and total creatine were measured before and after supplementation. A primed-continuous intravenous infusion of l-[1-13C]leucine and mass spectrometry were used to measure mixed-muscle protein fractional synthetic rate and indexes of whole body leucine metabolism (nonoxidative leucine disposal), leucine oxidation, and plasma leucine rate of appearance. CrM supplementation increased muscle total creatine (+13.1%, P < 0.05) with a trend toward an increase in phosphocreatine (+8.8%, P = 0.09). CrM supplementation did not increase muscle fractional synthetic rate but reduced leucine oxidation (−19.6%) and plasma leucine rate of appearance (−7.5%, P < 0.05) in men, but not in women. CrM did not increase total body mass or fat-free mass. We conclude that short-term CrM supplementation may have anticatabolic actions in some proteins (in men), but CrM does not increase whole body or mixed-muscle protein synthesis.

scholarly journals Glucocorticoid effects on insulin- and IGF-I-regulated muscle protein metabolism during aging

1998 ◽  
Vol 156 (1) ◽  
pp. 83-89 ◽  
Author(s):  
D Dardevet ◽  
C Sornet ◽  
I Savary ◽  
E Debras ◽  
P Patureau-Mirand ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Muscle Atrophy ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Recovery Period ◽  
Adult Rats ◽  
Igf I ◽  
Muscle Protein Metabolism ◽  
Old Rats

This study was performed to assess the effect of glucocorticoids (dexamethasone) on insulin- and IGF-I-regulated muscle protein metabolism in adult and old rats. Muscle atrophy occurred more rapidly in old rats, and recovery of muscle mass was impaired when compared with adults. Muscle wasting resulted mainly from increased protein breakdown in adult rat but from depressed protein synthesis in the aged animal. Glucocorticoid treatment significantly decreased the stimulatory effect of insulin and IGF-I on muscle protein synthesis in adult rats by 25.9 and 58.1% respectively. In old rats, this effect was even greater, being 49.3 and 100% respectively. With regard to muscle proteolysis, glucocorticoids blunted the anti-proteolytic action of insulin and IGF-I in both age groups. During the recovery period, adult rats reversed the glucocorticoid-induced resistance of muscle protein metabolism within 3 days, at which time old rats still exhibited the decrease in insulin-regulated proteolysis. In conclusion, the higher sensitivity of old rat muscle to glucocorticoids may in part result from the greater modification of the effects of insulin and IGF-I on muscle protein metabolism. These responses to glucocorticoids in old rats may be associated with the emergence of muscle atrophy with advancing age.

scholarly journals Muscle Protein Synthesis and Whole-Body Protein Turnover Responses to Ingesting Essential Amino Acids, Intact Protein, and Protein-Containing Mixed Meals with Considerations for Energy Deficit

Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2457 ◽  
Author(s):  
Jess A. Gwin ◽  
David D. Church ◽  
Robert R. Wolfe ◽  
Arny A. Ferrando ◽  
Stefan M. Pasiakos
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Energy Deficit ◽  
Whole Body ◽  
Intact Protein ◽  
Body Protein ◽  
Protein Feeding

Protein intake recommendations to optimally stimulate muscle protein synthesis (MPS) are derived from dose-response studies examining the stimulatory effects of isolated intact proteins (e.g., whey, egg) on MPS in healthy individuals during energy balance. Those recommendations may not be adequate during periods of physiological stress, specifically the catabolic stress induced by energy deficit. Providing supplemental intact protein (20–25 g whey protein, 0.25–0.3 g protein/kg per meal) during strenuous military operations that elicit severe energy deficit does not stimulate MPS-associated anabolic signaling or attenuate lean mass loss. This occurs likely because a greater proportion of the dietary amino acids consumed are targeted for energy-yielding pathways, whole-body protein synthesis, and other whole-body essential amino acid (EAA)-requiring processes than the proportion targeted for MPS. Protein feeding formats that provide sufficient energy to offset whole-body energy and protein-requiring demands during energy deficit and leverage EAA content, digestion, and absorption kinetics may optimize MPS under these conditions. Understanding the effects of protein feeding format-driven alterations in EAA availability and subsequent changes in MPS and whole-body protein turnover is required to design feeding strategies that mitigate the catabolic effects of energy deficit. In this manuscript, we review the effects, advantages, disadvantages, and knowledge gaps pertaining to supplemental free-form EAA, intact protein, and protein-containing mixed meal ingestion on MPS. We discuss the fundamental role of whole-body protein balance and highlight the importance of comprehensively assessing whole-body and muscle protein kinetics when evaluating the anabolic potential of varying protein feeding formats during energy deficit.

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.

scholarly journals Muscle Protein Synthesis Response to Exercise Training in Obese, Older Men and Women

2012 ◽  
Vol 44 (7) ◽  
pp. 1259-1266 ◽  
Author(s):  
GORDON I. SMITH ◽  
DENNIS T. VILLAREAL ◽  
DAVID R. SINACORE ◽  
KRUPA SHAH ◽  
BETTINA MITTENDORFER
Keyword(s):  
Protein Synthesis ◽  
Exercise Training ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Older Men ◽  
Men And Women ◽  
Response To Exercise ◽  
Older Men And Women

Addition of glutamine to essential amino acids and carbohydrate does not enhance anabolism in young human males following exercise

2006 ◽  
Vol 31 (5) ◽  
pp. 518-529 ◽  
Author(s):  
Sarah B. Wilkinson ◽  
Paul L. Kim ◽  
David Armstrong ◽  
Stuart M. Phillips
Keyword(s):  
Protein Synthesis ◽  
Muscle Glycogen ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Breakdown Rate ◽  
Body Protein ◽  
Post Exercise ◽  
Glycogen Resynthesis

We examined the effect of a post-exercise oral carbohydrate (CHO, 1 g·kg–1·h–1) and essential amino acid (EAA, 9.25 g) solution containing glutamine (0.3 g/kg BW; GLN trial) versus an isoenergetic CHO–EAA solution without glutamine (control, CON trial) on muscle glycogen resynthesis and whole-body protein turnover following 90 min of cycling at 65% VO2 peak. Over the course of 3 h of recovery, muscle biopsies were taken to measure glycogen resynthesis and mixed muscle protein synthesis (MPS), by incorporation of [ring-2H5] phenylalanine. Infusion of [1-13C] leucine was used to measure whole-body protein turnover. Exercise resulted in a significant decrease in muscle glycogen (p < 0.05) with similar declines in each trial. Glycogen resynthesis following 3 h of recovery indicated no difference in total accumulation or rate of repletion. Leucine oxidation increased 2.5 fold (p < 0.05) during exercise, returned to resting levels immediately post-exercise,and was again elevated at 3 h post-exercise (p < 0.05). Leucine flux, an index of whole-body protein breakdown rate, was reduced during exercise, but increased to resting levels immediately post-exercise, and was further increased at 3 h post-exercise (p < 0.05), but only during the CON trial. Exercise resulted in a marked suppression of whole-body protein synthesis (50% of rest; p < 0.05), which was restored post-exercise; however, the addition of glutamine did not affect whole-body protein synthesis post-exercise. The rate of MPS was not different between trials. The addition of glutamine to a CHO + EAA beverage had no effect on post-exercise muscle glycogen resynthesis or muscle protein synthesis, but may suppress a rise in whole-body proteolysis during the later stages of recovery.

Rapid measurement of whole body and forearm protein turnover using a [2H5]phenylalanine model

1989 ◽  
Vol 256 (5) ◽  
pp. E631-E639 ◽  
Author(s):  
G. N. Thompson ◽  
P. J. Pacy ◽  
H. Merritt ◽  
G. C. Ford ◽  
M. A. Read ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Rapid Assessment ◽  
Whole Body ◽  
Co2 Production ◽  
Constant Infusion ◽  
Body Protein ◽  
Normal Adults

Whole body protein turnover was measured in six normal adults using a model based on a primed constant infusion of [2H5]phenylalanine and, independently, by an established method of a primed constant infusion of [1-13C]leucine. Isotopic plateau in plasma was achieved within 2 h for [2H5]phenylalanine and, in four of the subjects who received a priming dose of [2H4]tyrosine, for [2H4]tyrosine. In all subjects whole body protein turnover measured with the phenylalanine model (mean protein synthesis, 2.65 +/- (SD) 0.16 g.kg-1.24 h-1; catabolism, 3.58 +/- 0.26 g.kg-1.24 h-1) was similar to that measured using the leucine model (synthesis, 3.09 +/- 0.27 g.kg-1.24 h-1; catabolism, 3.70 +/- 0.35 g.kg-1.24 h-1). Mean forearm fractional muscle protein synthesis calculated by the phenylalanine model was 0.06 +/- 0.03%/h, which compares closely with literature values derived by other methods. The phenylalanine model allows the rapid assessment of whole body and muscle protein turnover from plasma samples alone, obviating the need for measurement of expired air CO2 production or enrichment.

Anabolic resistance: the effects of aging, sexual dimorphism, and immobilization on human muscle protein turnoverThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 34 (3) ◽  
pp. 377-381 ◽  
Author(s):  
Michael J. Rennie
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Older Persons ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Anabolic Resistance ◽  
Muscle Protein Metabolism ◽  
The Right

In healthy active older persons, there is no derangement of muscle protein metabolism. However, there is a major deficit in the ability of older muscles to regulate their maintenance during feeding and exercise. The dose–response relationship between myofibrillar protein synthesis and the availability of essential amino acids (EAA) is shifted down and to the right, and giving extra amino acids is unable to overcome this. There is no sex difference in basal or fed muscle protein metabolism in the young, but postmenopausal women have a greater anabolic resistance than older men. Anabolic resistance is also shown by the decreased phosphorylation in the PKB–mTOR–eIF4BP1 pathway in response to increased EAA. The muscle synthetic system is refractory to EAA provision, irrespective of the availability of insulin, insulin-like growth factor 1, and growth hormone. However, insulin is a major regulator of muscle protein breakdown, and there is a blunting of the ability of older muscle to decrease proteolysis in response to low concentrations of insulin, such as those observed after a light breakfast. Providing more EAA seems not to be useful, and modern N-balance data confirm that the dietary protein requirements of older persons are not increased. The sigmoidal dose–response relationship between muscle protein synthesis and resistance exercise intensity is shifted downward and to the right in older men. Decreased physical activity itself, even in young subjects, can produce anabolic resistance of muscle protein synthesis, which cannot be overcome by increasing amino acid availability. Exercise may retune the amino acid and (or) insulin sensitivity of muscle in older people.

Epinephrine depletion exacerbates the fasting-induced protein breakdown in fast-twitch skeletal muscles

2013 ◽  
Vol 305 (12) ◽  
pp. E1483-E1494 ◽  
Author(s):  
Flávia A. Graça ◽  
Dawit A. P. Gonçalves ◽  
Wilian A. Silveira ◽  
Eduardo C. Lira ◽  
Valéria Ernestânia Chaves ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Physiological Role ◽  
Protein Breakdown ◽  
Muscle Protein Metabolism ◽  
Fast Twitch ◽  
Fasted Rats

The physiological role of epinephrine in the regulation of skeletal muscle protein metabolism under fasting is unknown. We examined the effects of plasma epinephrine depletion, induced by adrenodemedullation (ADMX), on muscle protein metabolism in fed and 2-day-fasted rats. In fed rats, ADMX for 10 days reduced muscle mass, the cross-sectional area of extensor digitorum longus (EDL) muscle fibers, and the phosphorylation levels of Akt. In addition, ADMX led to a compensatory increase in muscle sympathetic activity, as estimated by the rate of norepinephrine turnover; this increase was accompanied by high rates of muscle protein synthesis. In fasted rats, ADMX exacerbated fasting-induced proteolysis in EDL but did not affect the low rates of protein synthesis. Accordingly, ADMX activated lysosomal proteolysis and further increased the activity of the ubiquitin (Ub)-proteasome system (UPS). Moreover, expression of the atrophy-related Ub ligases atrogin-1 and MuRF1 and the autophagy-related genes LC3b and GABARAPl1 were upregulated in EDL muscles from ADMX-fasted rats compared with sham-fasted rats, and ADMX reduced cAMP levels and increased fasting-induced Akt dephosphorylation. Unlike that observed for EDL muscles, soleus muscle proteolysis and Akt phosphorylation levels were not affected by ADMX. In isolated EDL, epinephrine reduced the basal UPS activity and suppressed overall proteolysis and atrogin-1 and MuRF1 induction following fasting. These data suggest that epinephrine released from the adrenal medulla inhibits fasting-induced protein breakdown in fast-twitch skeletal muscles, and these antiproteolytic effects on the UPS and lysosomal system are apparently mediated through a cAMP-Akt-dependent pathway, which suppresses ubiquitination and autophagy.

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