scholarly journals Turnover of muscle protein in the fowl. Changes in rates of protein synthesis and breakdown during hypertrophy of the anterior and posterior latissimus dorsi muscles

1978 ◽  
Vol 176 (2) ◽  
pp. 407-417 ◽  
Author(s):  
G J Laurent ◽  
M P Sparrow ◽  
D J Millward
Keyword(s):  
Protein Synthesis ◽  
Latissimus Dorsi ◽  
Muscle Protein ◽  
Synthesis Rate ◽  
Muscle Fibres ◽  
Fractional Rate ◽  
Period 2 ◽  
Dna Contents ◽  
Anterior Latissimus Dorsi ◽  
The Difference

Measurements were made of the growth and of the changes in rates of protein turnover in the anterior latissimus dorsi muscle of the adult fowl in response to the attachment of a weight to one wing. Over 58 days there was a 140% increase in the protein content with similar increases in the RNA and DNA contents. The fractional rate of protein synthesis, measured by the continuous-infusion technique using [14C]proline, increased markedly during hypertrophy. This increase was mediated initially (after 1 day) by an increase in the RNA activity but at all other times reflected the higher RNA content. The rate of protein degradation, calculated from the difference between the synthesis and growth rates, appeared to increase and remain elevated for at least 4 weeks. At no time was there any suggestion of a fall in the rate of degradation. The following events are discussed as central to the changes that occur during skeletal-muscle hypertrophy. 1. Nuclear proliferation is necessary to maintain the characteristic synthesis rate because of the inability of existing nuclei to ‘manage’ increased protein synthesis for more than a limited period. 2. The increased protein breakdown during hypertrophy is consistent with the known over-production of a new muscle fibres and may indicate some ‘wastage’ during the growth. Such wastage may also be associated with myofibrillar proliferation. 3. Muscle stretch must be recognized as the major activator of growth and as such can be compared with the ‘pleiotypic activators’ that have been described for cells in culture.

scholarly journals The effect of protein depletion and repletion on muscle-protein turnover in the chick

1981 ◽  
Vol 194 (3) ◽  
pp. 811-819 ◽  
Author(s):  
M L MacDonald ◽  
R W Swick
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Control Diet ◽  
Breast Muscle ◽  
Synthesis Rate ◽  
Protein Depletion ◽  
Protein Mass ◽  
Fractional Rate

Rates of growth and protein turnover in the breast muscle of young chicks were measured in order to assess the roles of protein synthesis and degradation in the regulation of muscle mass. Rates of protein synthesis were measured in vivo by injecting a massive dose of L-[1-14C]valine, and rates of protein degradation were estimated as the difference between the synthesis rate and the growth rate of muscle protein. In chicks fed on a control diet for up to 7 weeks of age, the fractional rate of synthesis decreased from 1 to 2 weeks of age and then changed insignificantly from 2 to 7 weeks of age, whereas DNA activity was constant for 1 to 7 weeks. When 4-week-old chicks were fed on a protein-free diet for 17 days, the total amount of breast-muscle protein synthesized and degraded per day and the amount of protein synthesized per unit of DNA decreased. Protein was lost owing to a greater decrease in the rate of protein synthesis, as a result of the loss of RNA and a lowered RNA activity. When depleted chicks were re-fed the control diet, rapid growth was achieved by a doubling of the fractional synthesis rate by 2 days. Initially, this was a result of increased RNA activity; by 5 days, the RNA/DNA ratio also increased. There was no evidence of a decrease in the fractional degradation rate during re-feeding. These results indicate that dietary-protein depletion and repletion cause changes in breast-muscle protein mass primarily through changes in the rate of protein synthesis.

scholarly journals Turnover of muscle protein in the fowl (Gallus domesticus). Rates of protein synthesis in fast and slow skeletal, cardiac and smooth muscle of the adult fowl

1978 ◽  
Vol 176 (2) ◽  
pp. 393-401 ◽  
Author(s):  
G J Laurent ◽  
M P Sparrow ◽  
P C Bates ◽  
D J Millward
Keyword(s):  
Protein Synthesis ◽  
Smooth Muscle ◽  
Cardiac Muscle ◽  
Latissimus Dorsi ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Latissimus Dorsi Muscle ◽  
Gallus Domesticus ◽  
Synthesis Rate ◽  
Dorsi Muscle

Rates of protein synthesis in skeletal, cardiac and smooth muscle of fully grown fowl (Gallus domesticus) were determined in vivo by means of the constant infusion method using [14C]proline. In the anterior latissimus dorsi muscle, containing predominantly slow fibres, the average synthesis rate of non-collagen muscle proteins was 17.0 +/- 3.1% per day, a value higher than that obtained for cardiac muscle (13.8 +/- 1.3% per day) and for smooth muscle of the gizzard (12.0 +/- 1.9% per day). In the posterior latissimus dorsi muscle, containing predominantly fast fibres, synthesis rates were much lower (6.9 +/- 1.8% per day). In each case these average rates for the non-collagen protein were similar to the average rate for the sarcoplasmic and myofibrillar protein fractions. The RNA concentration of these four muscles showed that relative rates of protein synthesis were determined mainly by the relative RNA concentrations. The rate of protein synthesis per unit of DNA (the DNA activity) was similar in the two skeletal muscles, but somewhat lower in cardiac muscle and gizzard, possibly reflecting the larger proportion of less active cell types in these two muscles. These quantitative aspects of protein turnover in the two skeletal muscles are discussed in terms of the determination of ultimate size of the DNA unit, and in relation to muscle ultrastructure.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: Exogenous insulin does not increase muscle protein synthesis rate when administered systemically: a systematic review

2015 ◽  
Vol 173 (1) ◽  
pp. R25-R34 ◽  
Author(s):  
Jorn Trommelen ◽  
Bart B L Groen ◽  
Henrike M Hamer ◽  
Lisette C P G M de Groot ◽  
Luc J C van Loon
Keyword(s):  
Systematic Review ◽  
Older Adults ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Exogenous Insulin ◽  
Insulin Administration ◽  
Muscle Protein Synthesis Rate

BackgroundThough it is well appreciated that insulin plays an important role in the regulation of muscle protein metabolism, there is much discrepancy in the literature on the capacity of exogenous insulin administration to increase muscle protein synthesis ratesin vivoin humans.ObjectiveTo assess whether exogenous insulin administration increases muscle protein synthesis rates in young and older adults.DesignA systematic review of clinical trials was performed and the presence or absence of an increase in muscle protein synthesis rate was reported for each individual study arm. In a stepwise manner, multiple models were constructed that excluded study arms based on the following conditions: model 1, concurrent hyperaminoacidemia; model 2, insulin-induced hypoaminoacidemia; model 3, supraphysiological insulin concentrations; and model 4, older, more insulin resistant, subjects.ConclusionsFrom the presented data in the current systematic review, we conclude that: i) exogenous insulin and amino acid administration effectively increase muscle protein synthesis, but this effect is attributed to the hyperaminoacidemia; ii) exogenous insulin administered systemically induces hypoaminoacidemia which obviates any insulin-stimulatory effect on muscle protein synthesis; iii) exogenous insulin resulting in supraphysiological insulin levels exceeding 50 000 pmol/l may effectively augment muscle protein synthesis; iv) exogenous insulin may have a diminished effect on muscle protein synthesis in older adults due to age-related anabolic resistance; and v) exogenous insulin administered systemically does not increase muscle protein synthesis in healthy, young adults.

Chronic effects of β2 agonists on body composition and protein synthesis in the rat

1984 ◽  
Vol 4 (1) ◽  
pp. 83-91 ◽  
Author(s):  
P. W. Emery ◽  
N. J. Rothwell ◽  
M. J. Stock ◽  
P. D. Winter
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Binding Capacity ◽  
Body Weight Gain ◽  
Muscle Protein Synthesis ◽  
Body Protein ◽  
Fractional Rate ◽  
Brown Adipose ◽  
Β2 Agonists

Chronic treatment of rats with the β2-adrenergic agonists clenbuterol and fenoterol over 16–19 d raised energy intake, expenditure, and body weight gain but did not affect fat or energy deposition, and body protein gain was increased by 50 and 18%, respectively. Both drugs increased the protein content and mitochondrial GDP-binding capacity of brown adipose tissue. Clenbuterol did not affect plasma insulin, growth hormone, or triiodothyronine levels, although insulin levels were reduced by fenoterol. Both drugs caused hypertrophy of skeletal muscle (gastrocnemius), and muscle protein synthesis in vivo (fractional rate) was elevated by 34 and 26% in clenbuterol and fenoteroltreated rats, respectively.

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.

scholarly journals Human Muscle Protein Synthesis Rates after Intake of Hydrolyzed Porcine-Derived and Cows’ Milk Whey Proteins—A Randomized Controlled Trial

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 989 ◽  
Author(s):  
Bendtsen ◽  
Thorning ◽  
Reitelseder ◽  
Ritz ◽  
Hansen ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
G Protein ◽  
Whey Protein ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Muscle Proteins ◽  
Mixed Meal ◽  
The Impact

Abstract: Background: Whey protein has been shown to be one of the best proteins to stimulate muscle protein synthesis rate (MPS), but other high quality proteins, e.g., animal/porcine-derived, could have similar effects. Objective: To investigate the effects of hydrolyzed porcine proteins from blood (HPB) and muscle (HPM), in comparison to hydrolyzed whey protein (HW), on MPS after intake of 15 g alone or 30 g protein as part of a mixed meal. We hypothesized that the postprandial MPS would be similar for porcine proteins and whey protein. Design: Eighteen men (mean ± SD age: 24 ± 1 year; BMI: 21.7 ± 0.4 kg/m2) participated in the randomized, double-blind, three-way cross-over study. Subjects consumed the three test products (HPB, HPM and HW) in a random order in two servings at each test day. Serving 1 consisted of a drink with 15 g protein and serving 2 of a drink with 30 g protein together with a mixed meal. A flood-primed continuous infusion of (ring-13C6) phenylalanine was performed and muscle biopsies, blood and urine samples were collected for determination of MPS, muscle free leucine, plasma amino acid concentrations and urea excretion. Results: There were no statistical differences between the MPS measured after consuming 15 g protein alone or 30 g with a mixed meal (p = 0.53) of HPB (0.048 ± 0.007 vs. 0.049 ± 0.008%/h, resp.), HPM (0.063 ± 0.011 vs. 0.062 ± 0.011 %/h, resp.) and HW (0.058 ± 0.007 vs. 0.071 ± 0.013%/h, resp.). However, the impact of protein type on MPS reached statistical tendency (HPB vs. HPM (p = 0.093) and HPB vs. HW (p = 0.067)) with no difference between HPM and HW (p = 0.88). Plasma leucine, branched-chain, essential and total amino acids were generally higher for HPB and HW than HPM (p < 0.01), which reflected their content in the proteins. Muscle-free leucine was higher for HPB than HW and HPM (p < 0.05). Conclusion: Hydrolyzed porcine proteins from blood and muscle resulted in an MPS similar to that of HW, although with a trend for porcine blood proteins to be inferior to muscle proteins and whey. Consequently, these porcine-derived muscle proteins can be used similarly to whey protein to support maintenance of skeletal muscle as part of supplements and ingredients in foods.

Histochemical differentiation of extrafusal muscle fibres of the anterior latissimus dorsi in the chick

1980 ◽  
Vol 9 (6) ◽  
pp. 305-314 ◽  
Author(s):  
J.P. Toutant ◽  
M.N. Toutant ◽  
D. Renaud ◽  
G.H. Le Douarin
Keyword(s):  
Latissimus Dorsi ◽  
Muscle Fibres ◽  
Anterior Latissimus Dorsi

Mixed muscle and hepatic derived plasma protein metabolism is differentially regulated in older and younger men following resistance exercise

2005 ◽  
Vol 288 (5) ◽  
pp. E922-E929 ◽  
Author(s):  
M. Sheffield-Moore ◽  
D. Paddon-Jones ◽  
A. P. Sanford ◽  
J. I. Rosenblatt ◽  
A. G. Matlock ◽  
...  
Keyword(s):  
Acute Phase ◽  
Muscle Protein ◽  
Older Men ◽  
Moderate Intensity ◽  
Synthesis Rate ◽  
Leg Extension ◽  
Single Bout ◽  
Younger Men ◽  
The Difference ◽  
Exercise Induced

We sought to determine whether exercise-induced muscle protein turnover alters the subsequent production of hepatically derived acute-phase plasma proteins, and whether age affects how these proteins are regulated. We measured arteriovenous (a-v) balance and the synthesis of mixed muscle protein, albumin (A) and fibrinogen (F) before exercise (REST) and from the beginning of exercise to 10, 60, and 180 min following a single bout of moderate-intensity leg extension exercise (POST-EX) in postabsorptive untrained older ( n = 6) and younger ( n = 6) men using l-[ ring-2H5]phenylalanine (Phe). Subjects performed 6 sets of 8 repetitions of leg extension at 80% of their 1-RM (one-repetition maximum). All data are presented as the difference from REST (Δ from REST at 10, 60, and 180 min POST-EX). Mixed muscle fractional synthesis rate (FSR-M) increased significantly from the beginning of exercise until 10 min POST-EX in the older men (ΔFSR-M: 0.044%/h), whereas FSR-M in the younger men was not elevated until 180 min POST-EX (ΔFSR-M: 0.030%/h). FSR-A and FSR-F increased at all POST-EX periods in the older men (ΔFSR-A = 10 min: 1.90%/day; 60 min: 2.72%/day; 180 min: 2.78%/day; ΔFSR-F = 10 min: 1.00%/day; 60 min: 3.01%/day; 180 min: 3.73%/day). No change occurred in FSR-A in the younger men, but FSR-F was elevated from the beginning of exercise until 10 and 180 min POST-EX (10 min: 3.07%/day and 180 min: 3.96%/day). Net balance of Phe was positive in the older men in the immediate POST-EX period. Our data indicate that mixed muscle and hepatic derived protein synthesis is differentially regulated in younger and older men in response to a single bout of moderate-intensity leg extension exercise. Moreover, our data suggest that with age may come a greater need to salvage or make available amino acids from exercise-induced muscle protein breakdown to mount an acute-phase response.

Total and net muscle protein breakdown in infection determined by amino acid effluxes

1990 ◽  
Vol 258 (5) ◽  
pp. E856-E863 ◽  
Author(s):  
J. Sjolin ◽  
H. Stjernstrom ◽  
G. Friman ◽  
J. Larsson ◽  
J. Wahren
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Urinary Excretion ◽  
Protein Degradation ◽  
Muscle Protein ◽  
Human Infection ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Skeletal Muscle Protein ◽  
Mild Disease

The present investigation was undertaken to study whether, in human infection of varying severity, peripheral 3-methylhistidine efflux and urinary excretion are associated with net protein degradation and to estimate the protein synthesis rate from the combined effluxes of 3-methylhistidine, tyrosine, and phenylalanine. Quadruplicate femoral arteriovenous differences of 3-methylhistidine, tyrosine, and phenylalanine were multiplied by leg plasma flow in 15 infected patients. Leg effluxes for 3-methylhistidine, tyrosine, and phenylalanine were -0.074 +/- 0.011, -2.57 +/- 0.43, and -3.17 +/- 0.44 mumol/min, respectively. There was a significant linear relationship (P less than 0.01) between the effluxes of tyrosine and phenylalanine and the efflux and urinary excretion of 3-methylhistidine. A significant release of tyrosine and phenylalanine was observed in patients studied at the 3-methylhistidine level seen in normal healthy subjects. It is concluded that in infection 1) there is an increased breakdown of skeletal muscle protein and a reduced rate of protein synthesis, with the latter being relatively more important in patients with mild disease; and 2) urinary 3-methylhistidine excretion is associated with net skeletal muscle protein degradation for the patient group studied.

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