scholarly journals Response of muscle protein turnover to insulin after acute exercise and training

1986 ◽  
Vol 240 (3) ◽  
pp. 651-657 ◽  
Author(s):  
T A Davis ◽  
I E Karl
Keyword(s):  
Protein Synthesis ◽  
Exercise Training ◽  
Protein Turnover ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Muscle Protein Turnover ◽  
Exercise And Training ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

To determine whether the enhanced insulin-sensitivity of glucose metabolism in muscle after acute exercise also extends to protein metabolism, untrained and exercise-trained rats were subjected to an acute bout of exercise, and the responses of protein synthesis and degradation to insulin were measured in epitrochlearis muscles in vitro. Acute exercise of both untrained and trained rats decreased protein synthesis in muscle in the absence or presence of insulin, but protein degradation was not altered. Exercise training alone had no effect on protein synthesis or degradation in muscle in the absence or presence of insulin. Acute exercise or training alone enhanced the sensitivities of both protein synthesis and degradation to insulin, but the enhanced insulin-sensitivities from training alone were not additive to those after acute exercise. These results indicate that: a decrease in protein synthesis is the primary change in muscle protein turnover after acute exercise and is not altered by prior exercise training, and the enhanced insulin-sensitivities of metabolism of both glucose and protein after either acute exercise or training suggest post-binding receptor events.

scholarly journals Maternal Leucine-Rich Diet Minimises Muscle Mass Loss in Tumour-bearing Adult Rat Offspring by Improving the Balance of Muscle Protein Synthesis and Degradation

Biomolecules ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 229 ◽  
Author(s):  
Natália Angelo da Silva Miyaguti ◽  
Sarah Christine Pereira de Oliveira ◽  
Maria Cristina Cintra Gomes-Marcondes
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Control Diet ◽  
Nutritional Supplementation ◽  
Adult Offspring ◽  
Muscle Protein Turnover ◽  
Tumour Bearing ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Cachexia syndrome can affect cancer patients and new prevention strategies are required. Maternal nutritional supplementation can modify metabolic programming in the offspring, which lasts until adulthood. This could be a good approach against diseases such as cancer. A 3% leucine-rich diet treatment improved muscle protein turnover by modifying the mTOR and proteolytic pathways, thus we analysed whether maternal supplementation could ameliorate muscle protein turnover in adult offspring tumour-bearing rats. Pregnant Wistar rats received a control diet or 3% leucine-rich diet during pregnancy/lactation, and their weaned male offspring received a control diet until adulthood when they were distributed into following groups (n = 7–8 per group): C, Control; W, tumour-bearing; L, without tumour with a maternal leucine-rich diet; and WL, tumour-bearing with a maternal leucine-rich diet. Protein synthesis and degradation were assessed in the gastrocnemius muscle, focusing on the mTOR pathway, which was extensively altered in W group. However, the WL adult offspring showed no decrease in muscle weight, higher food intake, ameliorated muscle turnover, activated mTOR and p70S6K, and maintained muscle cathepsin H and calpain activities. Maternal leucine nutritional supplementation could be a positive strategy to improve muscle protein balance in cancer cachexia-induced muscle damage in adult offspring rats.

Human muscle protein synthesis and breakdown during and after exercise

2009 ◽  
Vol 106 (6) ◽  
pp. 2026-2039 ◽  
Author(s):  
Vinod Kumar ◽  
Philip Atherton ◽  
Kenneth Smith ◽  
Michael J. Rennie
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Protein Turnover ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mitochondrial Protein ◽  
Human Muscle ◽  
Muscle Protein Turnover ◽  
Amino Acid Availability

Skeletal muscle demonstrates extraordinary mutability in its responses to exercise of different modes, intensity, and duration, which must involve alterations of muscle protein turnover, both acutely and chronically. Here, we bring together information on the alterations in the rates of synthesis and degradation of human muscle protein by different types of exercise and the influences of nutrition, age, and sexual dimorphism. Where possible, we summarize the likely changes in activity of signaling proteins associated with control of protein turnover. Exercise of both the resistance and nonresistance types appears to depress muscle protein synthesis (MPS), whereas muscle protein breakdown (MPB) probably remains unchanged during exercise. However, both MPS and MPB are elevated after exercise in the fasted state, when net muscle protein balance remains negative. Positive net balance is achieved only when amino acid availability is increased, thereby raising MPS markedly. However, postexercise-increased amino acid availability is less important for inhibiting MPB than insulin, the secretion of which is stimulated most by glucose availability, without itself stimulating MPS. Exercise training appears to increase basal muscle protein turnover, with differential responses of the myofibrillar and mitochondrial protein fractions to acute exercise in the trained state. Aging reduces the responses of myofibrillar protein and anabolic signaling to resistance exercise. There appear to be few, if any, differences in the response of young women and young men to acute exercise, although there are indications that, in older women, the responses may be blunted more than in older men.

scholarly journals Comparison of protein synthesis and degradation in incubated and perfused muscle

1983 ◽  
Vol 212 (3) ◽  
pp. 649-653 ◽  
Author(s):  
A S Clark ◽  
W E Mitch
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Insulin Treatment ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Muscle Protein Degradation ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Rates of muscle protein synthesis and degradation measured in the perfused hindquarter were compared with those in incubated epitrochlearis muscles. With fed or starved mature rats, results without insulin treatment were identical. With insulin treatment, protein synthesis in perfused hindquarters was greater, though protein degradation was the same. Thus rates of muscle protein degradation estimated by these two methods in vitro correspond closely.

scholarly journals Serum extracellular vesicle miR-203a-3p content is associated with skeletal muscle mass and protein turnover during disuse atrophy and regrowth

2020 ◽  
Vol 319 (2) ◽  
pp. C419-C431
Author(s):  
Douglas W. Van Pelt ◽  
Ivan J. Vechetti ◽  
Marcus M. Lawrence ◽  
Kathryn L. Van Pelt ◽  
Parth Patel ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Weight Bearing ◽  
Mirna Content ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Small noncoding microRNAs (miRNAs) are important regulators of skeletal muscle size, and circulating miRNAs within extracellular vesicles (EVs) may contribute to atrophy and its associated systemic effects. The purpose of this study was to understand how muscle atrophy and regrowth alter in vivo serum EV miRNA content. We also associated changes in serum EV miRNA with protein synthesis, protein degradation, and miRNA within muscle, kidney, and liver. We subjected adult (10 mo) F344/BN rats to three conditions: weight bearing (WB), hindlimb suspension (HS) for 7 days to induce muscle atrophy, and HS for 7 days followed by 7 days of reloading (HSR). Microarray analysis of EV miRNA content showed that the overall changes in serum EV miRNA were predicted to target major anabolic, catabolic, and mechanosensitive pathways. MiR-203a-3p was the only miRNA demonstrating substantial differences in HS EVs compared with WB. There was a limited association of EV miRNA content to the corresponding miRNA content within the muscle, kidney, or liver. Stepwise linear regression demonstrated that EV miR-203a-3p was correlated with muscle mass and muscle protein synthesis and degradation across all conditions. Finally, EV miR-203a-3p expression was significantly decreased in human subjects who underwent unilateral lower limb suspension (ULLS) to induce muscle atrophy. Altogether, we show that serum EV miR-203a-3p expression is related to skeletal muscle protein turnover and atrophy. We suggest that serum EV miR-203a-3p content may be a useful biomarker and future work should investigate whether serum EV miR-203a-3p content is mechanistically linked to protein synthesis and degradation.

scholarly journals A comparison of rates of protein turnover in rat diaphragm in vivo and in vitro

1986 ◽  
Vol 233 (1) ◽  
pp. 279-282 ◽  
Author(s):  
V R Preedy ◽  
D M Smith ◽  
P H Sugden
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Rat Diaphragm ◽  
Degradation Rates ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Protein synthesis and degradation rates in diaphragms from fed or starved rats were compared in vivo and in vitro. For fed rats, synthesis rates in vivo were approximately twice those in vitro, but for starved rats rates were similar. Degradation rates were less in vivo than in vitro in diaphragms from either fed or starved rats.

Increased rates of muscle protein turnover and amino acid transport after resistance exercise in humans

1995 ◽  
Vol 268 (3) ◽  
pp. E514-E520 ◽  
Author(s):  
G. Biolo ◽  
S. P. Maggi ◽  
B. D. Williams ◽  
K. D. Tipton ◽  
R. R. Wolfe
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Amino Acid Transport ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Acid Transport ◽  
Isotopic Tracers ◽  
Muscle Protein Turnover ◽  
Synthesis And Degradation

The rates of protein synthesis and degradation and of amino acid transport were determined in the leg muscle of untrained postabsorptive normal volunteers at rest and approximately 3 h after a resistance exercise routine. The methodology involved use of stable isotopic tracers of amino acids, arteriovenous catheterization of the femoral vessels, and biopsy of the vastus lateralis muscle. During postexercise recovery, the rate of intramuscular phenylalanine utilization for protein synthesis increased above the basal value by 108 +/- 18%, whereas the rate of release from proteolysis increased by 51 +/- 17%. Muscle protein balance improved (P < 0.05) after exercise but did not become positive (from -15 +/- 12 to -6 +/- 3 nmol phenylalanine.min-1.100 ml leg volume-1). After exercise, rates of inward transport of leucine, lysine, and alanine increased (P < 0.05) above the basal state from 132 +/- 16 to 208 +/- 29, from 122 +/- 8 to 260 +/- 8, and from 384 +/- 71 to 602 +/- 89 nmol.min-1.100 ml leg-1, respectively. Transport of phenylalanine did not change significantly. These results indicate that, during recovery after resistance exercise, muscle protein turnover is increased because of an acceleration of synthesis and degradation. A postexercise acceleration of amino acid transport may contribute to the relatively greater stimulation of protein synthesis.

Protein turnover in different types of skeletal muscle during experimental hyperthyroidism in rats

1985 ◽  
Vol 109 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Ulf Angerås ◽  
Per-Olof Hasseigren
Keyword(s):  
Protein Synthesis ◽  
Protein Content ◽  
Protein Turnover ◽  
Extensor Digitorum Longus ◽  
Muscle Protein ◽  
Slow Muscle ◽  
Protein Breakdown ◽  
Different Types ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Abstract. Exeprimental hyperthyroidism was induced in rats by daily ip injection of triiodothyronine (T3; 100 μg/100 g body weight) during 3 or 10 days. Protein synthesis and degradation were measured in incubated soleus and extensor digitorum longus (EDL) muscles by determining rate of tyrosine incorporation into protein and release of tyrosine to the incubation medium respectively. Protein synthesis was unaffected by T3 administration during 3 or 10 days. Protein breakdown was significantly increased in soleus but unchanged in EDL in the 3-days experiment. Following administration of T3 for 10 days proteolysis was increased in both muslces. Weight of the soleus muscle was reduced after T3 for 3 days. After 10 days weight and protein content were reduced in both muscles. The study demonstrated that reduced muscle protein content following administration of T3 was the result of increased proteolysis, not decreased protein synthesis. The results further indicate that slow muscle (soleus) is more sensitive to the effects of thyroid hormone than fast muscle (EDL).

scholarly journals Pentoxifylline improves insulin action limiting skeletal muscle catabolism after infection

1999 ◽  
Vol 163 (1) ◽  
pp. 15-24 ◽  
Author(s):  
T Vary ◽  
D Dardevet ◽  
J Grizard ◽  
L Voisin ◽  
C Buffiere ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Protein Degradation ◽  
Muscle Protein ◽  
Plasma Concentrations ◽  
Skeletal Muscle Protein ◽  
Muscle Protein Metabolism ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

We investigated the ability of pentoxifylline (PTX) to modulate protein synthesis and degradation in the presence and absence of insulin during incubation of epitrochlearis muscle, 2 or 6 days after injection of Escherichia coli. On days 2 and 6 after infection, protein synthesis was inhibited by 25%, whereas proteolysis was enhanced by 75%. Insulin (2 nM) in vitro stimulated protein synthesis in muscles from infected rats to the same extent as in controls. The ability of insulin to limit protein degradation was severely blunted 48 h after infection. On day 6 after infection, insulin inhibited proteolysis to a greater extent than on day 2. PTX suppressed the increase in plasma concentrations of tumor necrosis factor more than 600-fold after injection of bacteria, and partially prevented the inhibition of protein synthesis and stimulation of protein degradation during sepsis. Moreover, PTX administration maintained the responsiveness of protein degradation to insulin during sepsis. Thus cytokines may influence skeletal muscle protein metabolism during sepsis, both indirectly through inhibition of the effects of insulin on proteolysis, and directly on the protein synthesis and degradation machinery.

Skeletal muscle protein synthesis and degradation in vitro: effects of temperature

1985 ◽  
Vol 249 (5) ◽  
pp. C464-C470 ◽  
Author(s):  
D. A. Essig ◽  
S. S. Segal ◽  
T. P. White
Keyword(s):  
Protein Synthesis ◽  
Specific Activity ◽  
Muscle Protein ◽  
Peripheral Region ◽  
Core Region ◽  
Tension Development ◽  
The Core ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

We compared the structure, function, protein synthesis, and degradation of 70- to 95-mg rat soleus muscles during 120 min of incubation at 20 and 37 degrees C. At 37 degrees C, muscles were characterized by a damaged central core region and a decline of isometric tension development during incubation. Protein synthesis in the core region at 37 degrees C was depressed relative to the peripheral region. At 20 degrees C, developed tension remained constant during incubation, and synthesis rates in the core region were not different from the peripheral region. Compared with fresh muscle, ATP concentration after incubation was not affected by temperature. After equilibration of phenylalanine specific activity between extracellular and intracellular spaces (60 min at 20 degrees C; 30 min at 37 degrees C), rates of protein synthesis at 20 [0.048 nmol tyrosine (Tyr) X mg wet mass-1 X 2 h-1] and 37 degrees C (0.160 nmol Tyr X mg wet mass-1 X 2 h-1) were linear up to 180 and 120 min, respectively. Rates of protein degradation at 20 (0.076 nmol Tyr X mg wet mass-1 X 2 h-1) and 37 degrees C (0.248 nmol Tyr X mg wet mass-1 X 2 h-1) measured after 60 min were linear up to 180 and 120 min, respectively. Incubation at 20 degrees C offers an approach to study 70- to 95-mg muscles in vitro without compromising structure and function.

scholarly journals The effect of glutamine on protein turnover in chick skeletal muscle in vitro

1990 ◽  
Vol 265 (2) ◽  
pp. 593-598 ◽  
Author(s):  
G Wu ◽  
J R Thompson
Keyword(s):  
Protein Synthesis ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Plasma Concentrations ◽  
Glutamine Concentration ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

The effect of glutamine on the rates of protein synthesis and degradation was studied in isolated chick extensor digitorum communis muscles incubated in the presence of plasma concentrations of amino acids. Addition of 0.5-15 mM-glutamine increases (P less than 0.01) intracellular glutamine concentrations by 31-670%. There is a positive relationship (r = 0.975, P less than 0.01) between intracellular glutamine concentration and the rate of muscle protein synthesis measured by the incorporation of [3H]phenylalanine. The stimulating effect of 15 mM-glutamine on protein synthesis was decreased from 58 to 19% in muscles incubated in the absence of tyrosine. The rates of protein degradation, estimated from [3H]phenylalanine release from muscle proteins prelabelled in vivo, decreased (P less than 0.05) by 15-30% in the presence of 4-15 mM-glutamine when compared with muscles incubated in the presence of physiological concentrations of glutamine (0.5-1 mM). Glutamine concentrations ranging from 2 to 15 mM appear to have an overall anabolic effect on chick skeletal muscles incubated in vitro.

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