Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization

1981 ◽  
Vol 51 (1) ◽  
pp. 73-77 ◽  
Author(s):  
K. R. Tucker ◽  
M. J. Seider ◽  
F. W. Booth
Keyword(s):  
Protein Synthesis ◽  
Gastrocnemius Muscle ◽  
Weight Lifting ◽  
Constant Infusion ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Fractional Rate ◽  
Gastrocnemius Muscles ◽  
Infusion Technique ◽  
Limb Immobilization

Fractional rates of protein synthesis in rats were determined by the constant-infusion technique. Rates of protein synthesis in the gastrocnemius muscle were significantly reduced from control values throughout a 7-day period of hindlimb immobilization and 1) significantly increased to control values during the first 6 h following the 7-day period of hindlimb immobilization; 2) remained at control values for the next 2 days; and 3) then significantly increased to about twice control values on the 4th day following immobilization. Exercise of sufficient duration and/or intensity affected a further increase in the protein synthesis rate during recovery from atrophy. For example, running on a motor-driven treadmill 1 h daily for 3 days after ending limb immobilization resulted in a significant increase in the fractional rate of protein synthesis in the gastrocnemius muscle on the 2nd day following immobilization. Also, weight lifting for 200 s on the 2nd day of protein synthesis in the gastrocnemius muscle. Thus increased usage of atrophied muscle was followed by an increased rate of protein synthesis.

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.

scholarly journals Stimulation of epidermal protein synthesis in vivo by topical triamcinolone acetonide

1987 ◽  
Vol 247 (3) ◽  
pp. 525-530 ◽  
Author(s):  
C S Harmon ◽  
J H Park
Keyword(s):  
Protein Synthesis ◽  
Triamcinolone Acetonide ◽  
Gastrocnemius Muscle ◽  
Specific Radioactivity ◽  
Topical Administration ◽  
Hairless Mouse ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Fractional Rate

The rate of epidermal protein synthesis in vivo was determined in the hairless mouse by a method in which a large dose of [3H]phenylalanine (150 mumol/100 g body wt.) is administered via the tail vein. The epidermal free phenylalanine specific radioactivity rapidly rose to a plateau value which by 10 min approached that of plasma, after which it declined. This dose of phenylalanine did not of itself alter protein synthesis rates, since incorporation of co-injected tracer doses of [3H]lysine and [14C]threonine was unaffected. The fractional rate of protein synthesis obtained for epidermis was 61.6%/day, whereas values for liver and gastrocnemius muscle in the same group of mice were 44%/day and 4.8%/day respectively. When expressed on the basis of RNA content, the value for epidermis (18.6 mg of protein/day per mg of RNA) was approx. 3-fold higher than those for liver and gastrocnemius muscle. Topical administration of 0.1% triamcinolone acetonide increased the epidermal fractional protein synthesis rate by 33% after 1 day and by 69% after 7 days, compared with vehicle-treated controls. These effects were entirely accounted for by the increase in protein synthesis rates per mg of RNA. RNA/protein ratios were unaffected by this treatment.

Glucocorticoid-induced skeletal muscle atrophy in vitro is attenuated by mechanical stimulation

1992 ◽  
Vol 262 (6) ◽  
pp. C1471-C1477 ◽  
Author(s):  
J. A. Chromiak ◽  
H. H. Vandenburgh
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Protein Content ◽  
Total Protein ◽  
Weight Lifting ◽  
Mechanical Activity ◽  
Synthesis Rate ◽  
Protein Synthesis Rate

Glucocorticoids induce rapid atrophy of fast skeletal myofibers in vivo, and either weight lifting or endurance exercise reduces this atrophy by unknown mechanisms. We examined the effects of the synthetic glucocorticoid dexamethasone (Dex) on protein turnover in tissue-cultured avian fast skeletal myofibers and determined whether repetitive mechanical stretch altered the myofiber response to Dex. In static cultures after 3-5 days, 10(-8) M Dex decreased total protein content 42-74%, total protein synthesis rates 38-56%, mean myofiber diameter 35%, myosin heavy chain (MHC) content 86%, MHC synthesis rate 44%, and fibronectin synthesis rate 29%. Repetitive 10% stretch-relaxations of the cultured myofibers for 60 s every 5 min for 3-4 days prevented 52% of the Dex-induced decrease in protein content, 42% of the decrease in total protein synthesis rate, 77% of the decrease in MHC content, 42% of the decrease in MHC synthesis rate, and 67% of the decrease in fibronectin synthesis rate. This in vitro model system will complement in vivo studies in understanding the mechanism by which mechanical activity and glucocorticoids interact to regulate skeletal muscle growth.

Estimation of tissue protein synthesis in rats fed diets labeled with (U-14C)tyrosine

1976 ◽  
Vol 231 (4) ◽  
pp. 1018-1023 ◽  
Author(s):  
ME Harney ◽  
RW Swick ◽  
NJ Benevenga
Keyword(s):  
Protein Synthesis ◽  
Specific Activity ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Constant Infusion ◽  
Liver Protein ◽  
Fractional Rate ◽  
Tissue Protein Synthesis ◽  
Physiological Approach ◽  
Infusion Technique

The rate of liver and muscle protein synthesis has been measured in 27 rats after feeding L-[U-14C]tyrosine in L-amino acid diets prepared as agar gels. Constant specific activity of the free tyrosine pool, as indicated by constant excretion of 14CO2, was reached within 2 h of feeding and was maintained for the remaining 6 h of the 8-h experiment. Muscle protein synthesis was decreased (P less than 0.05) in rats fed a 0.3% methionine diet compared with rats fed this diet supplemented with 0.51% cystine (fractional rate of synthesis, ks: 0.098 vs. 0.121). No effect (P greater than 0.05) of these diets on liver protein synthesis was observed (ks: 0.603 vs. 0.532). Protein synthetic rate was also determined by the constant-intravenous infusion technique in 17 rats fed unlabeled diets. The two techniques gave similar estimates. Restraint of the rats or the infusion of saline had no measurable effect on the rate of protein synthesis in rats fed labeled diets. This feeding technique is essentially equivalent to the constant-infusion technique and offers an easier, more physiological approach to achieving a steady state.

Assessment of the mathematical issues involved in measuring the fractional synthesis rate of protein using the flooding dose technique

1993 ◽  
Vol 84 (2) ◽  
pp. 177-183 ◽  
Author(s):  
David L. Chinkes ◽  
Judah Rosenblatt ◽  
Robert R. Wolfe
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Intracellular Concentration ◽  
Upper And Lower Bounds ◽  
Constant Infusion ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Underlying Assumption ◽  
Fractional Synthesis Rate ◽  
Fractional Synthesis

1. The fractional synthesis rate of protein is commonly measured by either the constant infusion method or the flooding dose method. The two methods often give different results. 2. An underlying assumption of the traditional flooding dose formula is that the protein synthesis rate is not stimulated by the flooding dose. A new formula for calculation of the fractional synthesis rate is derived with the alternative assumption that the protein synthesis rate is stimulated by an amount proportional to the change in the intracellular concentration of the infused amino acid. The alternative formula is: where EB and EF are the enrichments of bound and free amino acid, respectively (atom per cent excess), and C=1-(EF/EI), where EI is the enrichment of the infusate. This approach defines the lowest possible value for the fractional synthesis rate. The traditional equation gives a maximal value for the fractional synthesis rate. 3. When data from the literature are considered, the fractional synthesis rate of muscle protein as calculated by the constant infusion technique falls between the values of fractional synthesis rate calculated by the two flooding dose formulae when leucine is the tracer, suggesting that a flooding dose of leucine exerts a stimulatory effect on the rate of protein synthesis, but that the increase is not as great as the increase in the intracellular concentration of leucine. 4. The precision of the formula for the calculation of fractional synthesis rate is limited by the accuracy of the underlying assumptions regarding the effect of the flooding dose on the fractional synthesis rate. At present, the best approach would appear to be the use of both equations to calculate the upper and lower bounds of the true fractional synthesis rate.

Comparison of Constant Infusion and Flooding Dose Techniques to Measure Muscle Protein Synthesis Rate in Dogs

1992 ◽  
Vol 122 (4) ◽  
pp. 878-887 ◽  
Author(s):  
Farook Jahoor ◽  
Xiao-Jun Zhang ◽  
Hidefumi Baba ◽  
Yoichi Sakurai ◽  
Robert R. Wolfe
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Constant Infusion ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Muscle Protein Synthesis Rate

Muscle Protein and Amino Acid Turnover in Rats in Vivo: Effects of Short-Term and Prolonged Starvation

1996 ◽  
Vol 90 (6) ◽  
pp. 457-466 ◽  
Author(s):  
I. De Blaauw ◽  
N. E. P. Deutz ◽  
M. F. Von Meyenfeldt
Keyword(s):  
Body Weight ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Gastrocnemius Muscle ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Small Animals ◽  
Prolonged Starvation ◽  
Amino Acid Turnover ◽  
Tracer Dilution

1. Protein loss in muscle can be caused by decreased protein synthesis, increased breakdown or both. In small animals the tracer incorporation technique is mostly used to measure protein synthesis, but for degradation measurements in vitro or ex vivo settings are required. In human and large animal studies the arteriovenous dilution technique is used because it enables the measurement of synthesis and breakdown rates simultaneously. The applicability in small animals has not yet been proven. We used a starvation model to compare both techniques. 2. A primed constant infusion of l-[2,6-3H]phenylalanine was given to male Lewis rats after 16, 40, 64 and 112 h starvation. Protein synthesis rates of the gastrocnemius muscle were measured by the incorporation technique and compared with hindquarter protein turnover calculated in a two- and three-compartment arteriovenous dilution model. 3. Whole-body phenylalanine rate of appearance decreased from 456 ± 32 after 16 h to 334 ± 34 (nmol min−1 100 g−1 body weight) after 112 h starvation. Protein synthesis rates of the gastrocnemius muscle measured by the tracer incorporation technique decreased from 3.6 ± 0.4 after 16 h starvation to 2.2 ± 0.3 after 64 h starvation and 1.8 ± 0.4 (%/day) after 112h starvation. Hindquarter protein breakdown, calculated with the tracer dilution model, increased after 112 h starvation from 28 ± 12 to 77 ± 15 nmol min−1 100 g−1 body weight. Using the tracer dilution model, however, the calculated protein synthesis rate across the hindquarter also increased after prolonged starvation (29 ± 7 and 68 ± 16 nmol min−1 100 g−1 body weight after 16 and 112h respectively). In conjunction with this, calculated bidirectional membrane transport rates were also enhanced. Using valine and glutamine as tracers, the enhanced amino acid turnover rates were confirmed. 4. In conclusion, our results show that during short periods of starvation both methods give similar results. After prolonged starvation, however, an opposite change in disappearance rate and protein synthesis rate was observed. Assumptions made to calculate protein turnover using the arteriovenous dilution model may account for the discrepancy and care must be taken with the interpretation when using only one model in anaesthetized small animals.

scholarly journals Studies on the range of tissue protein synthesis in pigs: the effect of thyroid hormones

1982 ◽  
Vol 48 (3) ◽  
pp. 571-582 ◽  
Author(s):  
O. Simon ◽  
H. Bergner ◽  
R. Münchmeyer ◽  
Teresa Zebrowska
Keyword(s):  
Protein Synthesis ◽  
Thyroid Hormones ◽  
Growing Pigs ◽  
Constant Infusion ◽  
Kidney Cortex ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Kidney Medulla ◽  
Tissue Protein ◽  
Tissue Protein Synthesis

1. The effects of thyroid hormones on the range of tissue protein synthesis in growing pigs using the constant infusion technique with [14c]leucine and [14C]lysine were studied.2. During a 6 h infusion, samples were taken from blood and, at the end of the infusion, from liver, pancreas, stomach, small and large intestines, kidney cortex, kidney medulla, muscle and skin.3. Lower relative specific radioactivities of free leucine and lysine in several tissues were observed in the hormone-treated group than in the untreated one.4. The range of protein synthesis rate and the daily amount of protein synthesized in tissues was higher in all tissues after application of thyroid hormones.5. Assuming that the organs analysed represented 70% of the total trichloroacetic acid-precipitable protein of the pig, the estimated range of daily protein synthesis was 251–490 and 312–880 g in untreated and hormone-treated pigs respectively.

scholarly journals Resistance exercise training increases mixed muscle protein synthesis rate in frail women and men ≥76 yr old

1999 ◽  
Vol 277 (1) ◽  
pp. E118-E125 ◽  
Author(s):  
Kevin E. Yarasheski ◽  
Jina Pak-Loduca ◽  
Debbie L. Hasten ◽  
Kathleen A. Obert ◽  
Mary Beth Brown ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Training ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Weight Lifting ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Resistance Exercise Training

Muscle atrophy (sarcopenia) in the elderly is associated with a reduced rate of muscle protein synthesis. The purpose of this study was to determine if weight-lifting exercise increases the rate of muscle protein synthesis in physically frail 76- to 92-yr-old women and men. Eight women and 4 men with mild to moderate physical frailty were enrolled in a 3-mo physical therapy program that was followed by 3 mo of supervised weight-lifting exercise. Supervised weight-lifting exercise was performed 3 days/wk at 65–100% of initial 1-repetition maximum on five upper and three lower body exercises. Compared with before resistance training, the in vivo incorporation rate of [13C]leucine into vastus lateralis muscle protein was increased after resistance training in women and men ( P < 0.01), although it was unchanged in five 82 ± 2-yr-old control subjects studied two times in 3 mo. Maximum voluntary knee extensor muscle torque production increased in the supervised resistance exercise group. These findings suggest that muscle contractile protein synthetic pathways in physically frail 76- to 92-yr-old women and men respond and adapt to the increased contractile activity associated with progressive resistance exercise training.

scholarly journals Metabolic rate and rates of protein turnover in food-deprived cuttlefish, Sepia officinalis (Linnaeus 1758)

2016 ◽  
Vol 310 (11) ◽  
pp. R1160-R1168 ◽  
Author(s):  
Simon G. Lamarre ◽  
Tyson J. MacCormack ◽  
Antonio V. Sykes ◽  
Jennifer R. Hall ◽  
Ben Speers-Roesch ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Oxygen Consumption ◽  
Food Deprivation ◽  
Metabolic Response ◽  
Fold Increase ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Sepia Officinalis ◽  
Fractional Rate ◽  
Ubiquitin Proteasome

To determine the metabolic response to food deprivation, cuttlefish ( Sepia officinalis) juveniles were either fed, fasted (3 to 5 days food deprivation), or starved (12 days food deprivation). Fasting resulted in a decrease in triglyceride levels in the digestive gland, and after 12 days, these lipid reserves were essentially depleted. Oxygen consumption was decreased to 53% and NH4 excretion to 36% of the fed group following 3–5 days of food deprivation. Oxygen consumption remained low in the starved group, but NH4 excretion returned to the level recorded for fed animals during starvation. The fractional rate of protein synthesis of fasting animals decreased to 25% in both mantle and gill compared with fed animals and remained low in the mantle with the onset of starvation. In gill, however, protein synthesis rate increased to a level that was 45% of the fed group during starvation. In mantle, starvation led to an increase in cathepsin A-, B-, H-, and L-like enzyme activity and a 2.3-fold increase in polyubiquitin mRNA that suggested an increase in ubiquitin-proteasome activity. In gill, there was a transient increase in the polyubiquitin transcript levels in the transition from fed through fasted to the starved state and cathepsin A-, B-, H-, and L-like activity was lower in starved compared with fed animals. The response in gill appears more complex, as they better maintain rates of protein synthesis and show no evidence of enhanced protein breakdown through recognized catabolic processes.

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