scholarly journals Turnover of muscle protein in the fowl. Collagen content and turnover in cardiac and skeletal muscles of the adult fowl and the changes during stretch-induced growth

1978 ◽  
Vol 176 (2) ◽  
pp. 419-427 ◽  
Author(s):  
Geoffrey J. Laurent ◽  
Malcolm P. Sparrow ◽  
Peter C. Bates ◽  
David J. Millward
Keyword(s):  
Total Protein ◽  
Latissimus Dorsi ◽  
Skeletal Muscles ◽  
Collagen Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Collagen Content ◽  
Constant Infusion ◽  
Intracellular Protein ◽  
Total Muscle

The collagen content and the rate of collagen synthesis were measured in the anterior and posterior latissimus dorsi muscles and in heart from fully grown fowl. This was done by measuring the proline/hydroxyproline ratios in the muscle and by a constant infusion of [14C]proline. These measurements were also made during the hypertrophy of the anterior muscle in response to the attachment of a weight to one wing of the fowl. In the non-growing muscles the collagen content was higher in the anterior muscle (22.8% of total protein) than in the posterior muscle (9.5% of total protein) and lowest in the heart (3.8% of total protein). In the two skeletal muscles a little over half of the collagen was accounted for by internal collagen (i.e. perimysium and endomysium). Collagen synthesis in these non-growing muscles occurred at 0.59%/day in each of the two skeletal muscles and at 0.88%/day in the cardiac muscle. During hypertrophy the collagen content of the anterior muscle increased, but not as fast as intracellular protein, so that after 58 days the concentration had fallen from 22.8 to 14.4% of total protein. This may have resulted from an incomplete production of the epimysial sheath, since the concentration of internal collagen did not fall and as a result accounted for over 80% of the total in the enlarged muscle. Collagen synthesis increased 8-fold during the first week of the hypertrophy, but never amounted to more than 4% of the total muscle protein synthesis. When the net accumulation of collagen is compared with the increased rate of synthesis it is concluded that between 30 and 70% of the newly synthesized collagen may have been degraded.

scholarly journals The effect of intermittent changes in tension on protein and collagen synthesis in isolated rabbit muscles

1981 ◽  
Vol 198 (3) ◽  
pp. 491-498 ◽  
Author(s):  
R M Palmer ◽  
P J Reeds ◽  
G E Lobley ◽  
R H Smith
Keyword(s):  
Protein Synthesis ◽  
Total Protein ◽  
Collagen Synthesis ◽  
Muscle Protein ◽  
Lactate Concentration ◽  
Constant Tension ◽  
Intact Rabbit ◽  
Mechanical Stretching ◽  
Total Muscle

Isolated intact rabbit muscles were incubated in a medium containing radioactive proline. The rates of synthesis of collagen and total muscle protein after incubation with a constant tension or intermittent mechanical stretching were compared with the rates in vivo. Muscles incubated under a constant tension synthesized protein at 22% of the rate observed in vivo; intermittent mechanical stretching resulted in an increase of 73% in the rate of protein synthesis, to 38% of that found in vivo. Collagen synthesis was affected in the same way as total protein synthesis by both types of incubation, therefore the relative rates of collagen and total protein synthesis were unchanged. ATP concentration in the isolate muscles and the uptake of glucose from the medium were increased by intermittent mechanical stretching. Incubating the muscles with a gas phase containing 5% O2 decreased the rate of protein synthesis, abolished the effect of intermittent mechanical stretching, lowered the concentration of ATP and increased the lactate concentration. The rate of protein synthesis in muscles maintained with a constant or intermittently applied tension was not affected by a previous period of incubation with the other type of stimulus.

Role of insulin and IGF-I in activation of muscle protein synthesis after oral feeding

1996 ◽  
Vol 270 (4) ◽  
pp. E614-E620 ◽  
Author(s):  
E. Svanberg ◽  
H. Zachrisson ◽  
C. Ohlsson ◽  
B. M. Iresjo ◽  
K. G. Lundholm
Keyword(s):  
Protein Synthesis ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Oral Feeding ◽  
Myofibrillar Proteins ◽  
Diabetic Mice ◽  
Igf I ◽  
Stimulation Of

The aim was to evaluate the role of insulin and insulin-like growth factor I (IGF-I) in activation of muscle protein synthesis after oral feeding. Synthesis rate of globular and myofibrillar proteins in muscle tissue was quantified by a flooding dose of radioactive phenylalanine. Muscle tissue expression of IGF-I mRNA was measured. Normal (C57 Bl) and diabetic mice (type I and type II) were subjected to an overnight fast (18 h) with subsequent refeeding procedures for 3 h with either oral chow intake or provision of insulin, IGF-I, glucose, and amino acids. Anti-insulin and anti-IGF-I were provided intraperitoneally before oral refeeding in some experiments. An overnight fast reduced synthesis of both globular (38 +/- 3%) and myofibrillar proteins (54 +/- 3%) in skeletal muscles, which was reversed by oral refeeding. Muscle protein synthesis, after starvation/ refeeding, was proportional and similar to changes in skeletal muscle IGF-I mRNA expression. Diabetic mice responded quantitatively similarly to starvation/refeeding in muscle protein synthesis compared with normal mice (C57 Bl). Both anti-insulin and anti-IGF-I attenuated significantly the stimulation of muscle protein synthesis in response to oral feeding, whereas exogenous provision of either insulin or IGF-I to overnight-starved and freely fed mice did not clearly stimulate protein synthesis in skeletal muscles. Our results support the suggestion that insulin and IGF-I either induce or facilitate the protein synthesis machinery in skeletal muscles rather than exerting a true stimulation of the biosynthetic process during feeding.

scholarly journals [3H]proline incorporation and hydroxyproline concentration in articular cartilage during the development of osteoarthritis caused by immobilization. A study in vivo with rabbits

1981 ◽  
Vol 200 (2) ◽  
pp. 435-440 ◽  
Author(s):  
T Videman ◽  
I Eronen ◽  
T Candolin
Keyword(s):  
Total Protein ◽  
Collagen Synthesis ◽  
Weight Bearing ◽  
Specific Radioactivity ◽  
Collagen Content ◽  
Synthetic Activity ◽  
Synthesis Rate ◽  
Hydroxyproline Concentration ◽  
Proline Incorporation

Proline metabolism in vivo was studied during the development of immobilization osteoarthritis in rabbits. Collagen content was measured as the hydroxyproline concentration of the tissue in question. The incorporation of [3H]proline was used as the indicator for total protein synthesis; collagen synthesis rate was estimated from measurements of the specific radioactivity of hydroxyproline. Cartilage samples from knee and hip joints were analysed after 3, 7, 11, 18, 35 and 56 days of immobilization. The total protein and collagen synthesis rates of the immobilized legs increased and reached a maximum after 11-35 days. Although they decreased thereafter, these rates remained elevated to the end of the experiment. A slight increase in the synthetic activity of the non-immobilized contralateral legs was also detected after 7--18 days of immobilization. The isotope incorporation was markedly higher in tibial marginal tissue than in weight-bearing cartilage. In spite of the increased synthesis, no clear changes were found in the collagen content of the tissues studied during the experiment.

Effect of Dietary Restriction on Protein Synthesis and Wound Healing after Surgery in the Rat

1995 ◽  
Vol 89 (4) ◽  
pp. 383-388 ◽  
Author(s):  
Peter W. Emery ◽  
Peter Sanderson
Keyword(s):  
Wound Healing ◽  
Protein Synthesis ◽  
Dietary Restriction ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Chronically Ill ◽  
Abdominal Muscle ◽  
Collagen Content ◽  
Synthesis Rate ◽  
Protein Synthesis Rate

1. The healing of an abdominal muscle wound after surgery is associated with a considerable increase in the rate of protein synthesis. We have investigated whether this increase in protein synthesis is affected by chronic undernutrition, and whether this causes a delay in wound healing. 2. A group of rats was fed 58% of the voluntary food intake of a matched control group. After 7 days half the rats in each group underwent abdominal surgery. Forty-eight hours later all the rats were killed and muscle protein synthesis rate was measured by the flooding dose technique. 3. In a second experiment using the same dietary regimen rats were placed in metabolic cages after surgery and killed 7 days later. In addition to measurements of muscle protein synthesis, wound breaking strength was measured with a tensiometer and collagen content was also measured at the wound site. 4. Dietary restriction caused a loss of body weight, a decrease in nitrogen balance and a deficit in muscle protein mass. It also caused a decrease in protein synthesis rate in gastrocnemius muscle and in parts of the abdominal muscle distant from the site of the wound. However, it had no effect on the rate of muscle protein synthesis at the site of the wound either 2 or 7 days after surgery. The tensile strength and the collagen content of the wound were also unaffected by food restriction. 5. It is concluded that the wound healing process is uniquely protected from the effects of moderate undernutrition such as might be experienced by a chronically ill patient.

Coordinated increase in albumin, fibrinogen, and muscle protein synthesis during hemodialysis: role of cytokines

2004 ◽  
Vol 286 (4) ◽  
pp. E658-E664 ◽  
Author(s):  
Dominic S. C. Raj ◽  
Elizabeth A. Dominic ◽  
Robert Wolfe ◽  
Vallabh O. Shah ◽  
Arthur Bankhurst ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Constant Infusion ◽  
Fractional Synthesis ◽  
Stage Renal Disease ◽  
End Stage ◽  
Esrd Patients

Serum albumin, fibrinogen levels, and lean body mass are important predictors of outcome in end-stage renal disease (ESRD). We estimated the fractional synthesis rates of albumin (FSR-A), fibrinogen (FSR-F), and muscle protein (FSR-M) in nine ESRD patients and eight controls, using primed constant infusion of l-[ ring-13C6]phenylalanine. Cytokine profile and arteriovenous balance of amino acids were also measured. ESRD patients were studied before (Pre-HD) and during hemodialysis (HD). Plasma IL-6, IL-10, and C-reactive protein increased significantly during HD. Despite a decrease in the delivery of amino acids to the leg, the outflow of the amino acids increased during HD. The net balance of amino acids became more negative during HD, indicating release from the muscle. HD increased leg muscle protein synthesis (45%) and catabolism (108%) but decreased whole body proteolysis (15%). FSR-A during HD (9.7 ± 0.9%/day) was higher than pre-HD (6.5 ± 0.9%/day) and controls (5.8 ± 0.5%/day, P < 0.01). FSR-F increased during HD (19.7 ± 2.6%/day vs. 11.8 ± 0.6%/day, P < 0.01), but it was not significantly different from that of controls (14.4 ± 1.4%/day). FSR-M intradialysis (1.77 ± 0.19%/day) was higher than pre-HD (1.21 ± 0.25%/day) and controls (1.30 ± 0.32%/day, P < 0.001). Pre-HD FSR-A, FSR-F, and FSR-M values were comparable to those of controls. There was a significant and positive correlation between plasma IL-6 and the FSRs. Thus, in ESRD patients without metabolic acidosis, the fractional synthesis rates of albumin, fibrinogen, and muscle protein are not decreased pre-HD. However, HD increases the synthesis of albumin, fibrinogen, and muscle protein. The coordinated increase in the FSRs is facilitated by constant delivery of amino acids derived from the muscle catabolism and intradialytic increase in IL-6.

The Time Course for Elevated Muscle Protein Synthesis Following Heavy Resistance Exercise

1995 ◽  
Vol 20 (4) ◽  
pp. 480-486 ◽  
Author(s):  
J. Duncan MacDougall ◽  
Martin J. Gibala ◽  
Mark A. Tarnopolsky ◽  
Jay R. MacDonald ◽  
Stephen A. Interisano ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Training ◽  
Time Course ◽  
Biceps Brachii ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Training Session ◽  
Constant Infusion ◽  
Heavy Resistance Training

It has been shown that muscle protein synthetic rate (MPS) is elevated in humans by 50% at 4 hrs following a bout of heavy resistance training, and by 109% at 24 hrs following training. This study further examined the time course for elevated muscle protein synthesis by examining its rate at 36 hrs following a training session. Six healthy young men performed 12 sets of 6- to 12-RM elbow flexion exercises with one arm while the opposite arm served as a control. MPS was calculated from the in vivo rate of incorporation of L-[1,2−13C2] leucine into biceps brachii of both arms using the primed constant infusion technique over 11 hrs. At an average time of 36 hrs postexercise, MPS in the exercised arm had returned to within 14% of the control arm value, the difference being nonsignificant. It is concluded that following a bout of heavy resistance training, MPS increases rapidly, is more than double at 24 hrs, and thereafter declines rapidly so that at 36 hrs it has almost returned to baseline. Key words: L-[−13C] leucine, muscle hypertrophy, training frequency, mass spectrometry

scholarly journals Downregulation of let-7 by Electrical Acupuncture Increases Protein Synthesis in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Ying Huang ◽  
Manshu Yu ◽  
Akihiro Kuma ◽  
Janet D. Klein ◽  
Yanhua Wang ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
High Sensitivity ◽  
Luciferase Reporter ◽  
C2c12 Myotubes ◽  
Electrical Acupuncture ◽  
The Impact ◽  
Serum Exosomes

BackgroundOur previous study found that acupuncture with low frequency electrical stimulation (Acu/LFES) prevents muscle atrophy by attenuation of protein degradation in mice. The current study examines the impact of Acu/LFES on protein synthesis.MethodC57/BL6 mice received Acu/LFES treatment on hindlimb for 30 min once. Acu/LFES points were selected by WHO Standard Acupuncture Nomenclature and electric stimulation applied using an SDZ-II Electronic acupuncture instrument. Muscle protein synthesis was measured by the surface-sensing of translation (SUnSET) assay. Exosomes were isolated using serial centrifugation and concentration and size of the collected exosomes were measured using a NanoSight instrument. The mature microRNA library in serum exosomes was validated using a High Sensitivity DNA chip.ResultsProtein synthesis was enhanced in the both hindlimb and forelimb muscles. Blocking exosome secretion with GW4869 decreased the Acu/LFES-induced increases in protein synthesis. MicroRNA-deep sequencing demonstrated that four members of the Let-7 miRNA family were significantly decreased in serum exosomes. Real time qPCR further verified Acu/LFES-mediated decreases of let-7c-5p in serum exosomes and skeletal muscles. In cultured C2C12 myotubes, inhibition of let-7c not only increased protein synthesis, but also enhanced protein abundance of Igf1 and Igf1 receptors. Using a luciferase reporter assay, we demonstrated that let-7 directly inhibits Igf1.ConclusionAcu/LFES on hindlimb decreases let-7-5p leading to upregulation of the Igf1 signaling and increasing protein synthesis in both hindlimb and forelimb skeletal muscles. This provides a new understanding of how the electrical acupuncture treatment can positively influence muscle health.

scholarly journals Potato Protein Isolate Stimulates Muscle Protein Synthesis at Rest and with Resistance Exercise in Young Women

Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1235 ◽  
Author(s):  
Sara Y. Oikawa ◽  
Ravninder Bahniwal ◽  
Tanya M. Holloway ◽  
Changhyun Lim ◽  
Jonathan C. McLeod ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Young Women ◽  
Total Protein ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Control Diet ◽  
Potato Protein ◽  
Opposite Limb

Skeletal muscle myofibrillar protein synthesis (MPS) increases in response to protein feeding and to resistance exercise (RE), where each stimuli acts synergistically when combined. The efficacy of plant proteins such as potato protein (PP) isolate to stimulate MPS is unknown. We aimed to determine the effects of PP ingestion on daily MPS with and without RE in healthy women. In a single blind, parallel-group design, 24 young women (21 ± 3 years, n = 12/group) consumed a weight-maintaining baseline diet containing 0.8 g/kg/d of protein before being randomized to consume either 25 g of PP twice daily (1.6 g/kg/d total protein) or a control diet (CON) (0.8 g/kg/d total protein) for 2 wks. Unilateral RE (~30% of maximal strength to failure) was performed thrice weekly with the opposite limb serving as a non-exercised control (Rest). MPS was measured by deuterated water ingestion at baseline, following supplementation (Rest), and following supplementation + RE (Exercise). Ingestion of PP stimulated MPS by 0.14 ± 0.09 %/d at Rest, and by 0.32 ± 0.14 %/d in the Exercise limb. MPS was significantly elevated by 0.20 ± 0.11 %/d in the Exercise limb in CON (p = 0.008). Consuming PP to increase protein intake to levels twice the recommended dietary allowance for protein augmented rates of MPS. Performance of RE stimulated MPS regardless of protein intake. PP is a high-quality, plant-based protein supplement that augments MPS at rest and following RE in healthy young women.

Early change in skeletal muscle protein synthesis after limb immobilization of rats

1979 ◽  
Vol 47 (5) ◽  
pp. 974-977 ◽  
Author(s):  
F. W. Booth ◽  
M. J. Seider
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Control Level ◽  
Constant Infusion ◽  
Initial Time ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Limb Immobilization

The atrophy of skeletal muscle accruing from disuse, or limb immobilization, is caused by a decreased rate of protein synthesis and an increased rate of protein degradation. Currently, little information is available regarding the initial time of the decline in the rate of protein synthesis in skeletal muscle. The purpose of the present study was to determine, as precisely as possible, the time at which the protein synthesis rate first begins to decline in skeletal muscle, utilizing immobilized limbs of rats for a model. A constant-infusion technique employing [14C]tyrosine was used to estimate protein synthesis rates. During the first 6 h of immobilization, a significant decline of 37% in the fractional rate of protein synthesis from the control level of 5.7%/day was observed. These results suggest that very early changes are occurring in molecular events that regulate protein synthesis in disused or immobilized skeletal muscle.

Insulin responsiveness of protein metabolism in vivo following bedrest in humans

1988 ◽  
Vol 255 (4) ◽  
pp. E548-E558 ◽  
Author(s):  
R. E. Shangraw ◽  
C. A. Stuart ◽  
M. J. Prince ◽  
E. J. Peters ◽  
R. R. Wolfe
Keyword(s):  
Nitrogen Balance ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Control Period ◽  
Skeletal Muscle Atrophy ◽  
Constant Infusion ◽  
Negative Nitrogen Balance ◽  
Leucine Oxidation ◽  
Oxidation Rates ◽  
Dose Dependent

To test the influence of bedrest on insulin regulation of leucine metabolism, six normal young men were subjected to a five-step hyperinsulinemic euglycemic clamp before and after 7 days of strict bedrest. A primed-constant infusion of [1-13C]leucine at 0.12 +/- 0.02 mumol.kg-1.min-1 was used. Before bedrest, the basal rate of appearance (Ra) of intracellular leucine and leucine oxidation were 2.79 +/- 0.17 and 0.613 +/- 0.070 mumol.kg-1.min-1, respectively. Insulin caused a dose-dependent reduction of the intracellular leucine Ra and leucine oxidation to a minimum of 1.64 +/- 0.08 and 0.322 +/- 0.039 mumol.kg-1.min-1, respectively, in nonbedrested subjects (P less than 0.001). Insulin also caused a dose-dependent reduction of plasma leucine concentration from 95 +/- 4 to 38 +/- 2 mumol/l (P less than 0.001). After bedrest, subjects exhibited decreased glucose tolerance and increased endogenous insulin secretion, but basal and insulin-suppressed intracellular leucine Ra and leucine oxidation rates were not different from control. Magnetic resonance imaging of the back and lower extremities revealed a 1-4% decrease in muscle volume and a 2-5% increase in fat volume secondary to bedrest. Bedrest also resulted in a negative nitrogen balance as compared with the control period, with an average cumulative loss of 6.3 g of nitrogen after 6 days. Urinary 3-methyl-L-histidine excretion was unchanged by bed rest. Thus because negative nitrogen balance and skeletal muscle atrophy occurred in six rested subjects in the absence of changes in the two indices of protein breakdown used in this study (3-methyl-L-histidine release and leucine release), it seems likely that muscle protein synthesis was inhibited.

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