Protein synthesis rate is not suppressed in rat heart during senescence

The purpose of these experiments was to determine whether mixed protein synthesis rates in hearts of Fischer 344 rats were decreased from maturity to senescence. When compared with 12-mo-old rat hearts, hearts from 23- to 25-mo-old rats had 13% lower concentrations of noncollagen protein, 9% less non-collagen protein per heart, 10% higher ratio of heart wet weight-to-body weight, and no difference in the basal rate of mixed protein synthesis, when expressed as fractional rate per day. Despite the 9% decrease in total noncollagen protein in 23- to 25-mo-old rat hearts, the derived value for milligrams protein synthesized per day was not different between age groups. When triiodothyronine was given for 3 days to mature and senescent rats, fractional rates of mixed protein synthesis were increased by similar percents (57–70%) in hearts from these two age groups. Basal and triiodothyronine-stimulated RNA concentrations in hearts of 12-mo-old and 23- to 25-mo-old rats were not different. These observations showed no decrease in either the basal or the maximal thyroid-stimulated rates of mixed protein synthesis in the hearts between mature and senescent rats. Thus an aging-programmed downregulation of mixed protein synthesis rates within cardiac muscle did not occur in the senescent Fischer 344 rat heart in this study.

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PP247-SUN VITAMIN D ADMINISTRATION POSITIVELY REGULATES FASTED MUSCLE PROTEIN SYNTHESIS RATE IN VITAMIN D DEPLETED OLD RATS

Clinical Nutrition ◽

10.1016/s0261-5614(13)60292-7 ◽

2013 ◽

Vol 32 ◽

pp. S116

Author(s):

A. Chanet ◽

J. Salles ◽

C. Giraudet ◽

A. Berry ◽

M.-L. Collin ◽

...

Keyword(s):

Vitamin D ◽

Protein Synthesis ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Synthesis Rate ◽

Protein Synthesis Rate ◽

Old Rats ◽

Muscle Protein Synthesis Rate

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Effect of fast dietary proteins on muscle protein synthesis rate and muscle strength in ad libitum-fed and energy-restricted old rats

British Journal Of Nutrition ◽

10.1017/s0007114511002182 ◽

2011 ◽

Vol 106 (11) ◽

pp. 1683-1690 ◽

Cited By ~ 14

Author(s):

Stéphane Walrand ◽

Aude Zangarelli ◽

Christelle Guillet ◽

Jérôme Salles ◽

Karine Soulier ◽

...

Keyword(s):

Protein Synthesis ◽

Muscle Strength ◽

Muscle Mass ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Synthesis Rate ◽

Protein Synthesis Rate ◽

Old Rats ◽

And Function ◽

Muscle Protein Synthesis Rate

Sarcopenia is defined as age-related loss of muscle mass and strength. Energy restriction (ER) delays fibre loss by limiting the accumulated deleterious effects of reactive oxygen species on muscle. However, insufficient protein intake during ER might affect muscle mass and function. We hypothesised that ingestion of fast-digested proteins such as whey protein (WP) improves muscle protein synthesis and muscle strength in aged ER rats. The effect of WP or casein (CAS, slow protein) on muscle mass, protein synthesis and strength was evaluated in 21-month-old rats fed for 5 months either ad libitum (AL) or a 40 % protein and energy-restricted (PER) or 40 % AL-isonitrogenous ER diet. The nitrogen balance was reduced in PER-CAS rats only ( − 48 % v. AL-CAS). WP stimulated muscle protein synthesis rates compared with CAS in all groups (+21,+37 and +34 % in AL, PER and ER conditions, respectively). Muscle strength was higher in ER rats than in AL rats (+23 and +12 % for WP or CAS, respectively). Muscle performance tended to be greater in ER rats fed WP than in ER-CAS rats (P < 0·09). In conclusion, we observed that long-term ER combined with maintained protein intake had a beneficial impact on muscle protein synthesis rate and function during ageing.

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Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization

Journal of Applied Physiology ◽

10.1152/jappl.1981.51.1.73 ◽

1981 ◽

Vol 51 (1) ◽

pp. 73-77 ◽

Cited By ~ 44

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.

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

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00459.2015 ◽

2016 ◽

Vol 310 (11) ◽

pp. R1160-R1168 ◽

Cited By ~ 12

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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Differential rates of protein synthesis in vitro and RNA contents in rat heart ventricular and atrial muscle

Biochemical Journal ◽

10.1042/bj2140497 ◽

1983 ◽

Vol 214 (2) ◽

pp. 497-502 ◽

Cited By ~ 11

Author(s):

D M Smith ◽

P H Sugden

Keyword(s):

Protein Synthesis ◽

Rat Heart ◽

Synthesis Rate ◽

Protein Synthesis Rate ◽

Plasma Amino Acids ◽

Rna Content ◽

Atrial Muscle ◽

Content Ratio ◽

Rat Growth

The rates of protein synthesis in perfused rat heart ventricular or atrial muscle were measured by incorporation of [U-14C]phenylalanine in the presence of the remaining plasma amino acids. Atrial protein-synthesis rates were about twice the ventricular rates. Atrial RNA contents were also about twice the ventricular contents. Thus the efficiencies of protein synthesis (protein-synthesis rate/RNA) in the two compartments were similar. There were marked differences in ventricular and atrial RNA contents during the course of rat growth. Atrial RNA content was always greater than ventricular content and declined more slowly during growth, producing a 2-fold change in atrial/ventricular RNA-content ratio between the 88 g and 370 g rat groups.

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Stimulation of epidermal protein synthesis in vivo by topical triamcinolone acetonide

Biochemical Journal ◽

10.1042/bj2470525 ◽

1987 ◽

Vol 247 (3) ◽

pp. 525-530 ◽

Cited By ~ 5

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.

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

Acta Endocrinologica ◽

10.1530/eje-14-0902 ◽

2015 ◽

Vol 173 (1) ◽

pp. R25-R34 ◽

Cited By ~ 15

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.

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Relationship between glutamine concentration and protein synthesis in rat skeletal muscle

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1988.255.2.e166 ◽

1988 ◽

Vol 255 (2) ◽

pp. E166-E172 ◽

Cited By ~ 19

Author(s):

M. M. Jepson ◽

P. C. Bates ◽

P. Broadbent ◽

J. M. Pell ◽

D. J. Millward

Keyword(s):

Protein Synthesis ◽

Protein Deficiency ◽

Synthesis Rate ◽

Protein Synthesis Rate ◽

Glutamine Concentration ◽

E Coli ◽

Protein Group ◽

Highly Correlated ◽

Rna Concentration

Muscle glutamine concentration ([GLN]) and protein synthesis rate (Ks) have been examined in vivo in well-fed, protein-deficient, starved, and endotoxemic rats. With protein deficiency (8 or 5% casein diet), [GLN] fell from 7.70 to 5.58 and 3.56 mmol/kg in the 8 and 5% diet groups, with Ks falling from 15.42 to 9.1 and 6.84%/day. Three-day starvation reduced [GLN] and Ks to 2.38 mmol/kg and 5.6%/day, respectively. In all these groups food intakes and insulin were generally well maintained (except in the starved group), whereas free 3,5,3'-triiodothyronine (T3) was depressed in the starved and 5% protein group. The E. coli lipopolysaccharide endotoxin (3 mg/kg) reduced [GLN] to 5.85 and 4.72 mmol/kg and Ks to 10.5 and 9.10%/day in two well-fed groups. Insulin levels were increased, and free T3 levels fell. Combined protein deficiency and endotoxemia further reduced [GLN] and Ks to 1.88 mmol/kg and 4.01%/day, respectively, in the 5% protein rats. Changes in both ribosomal activity (KRNA) and concentration (RNA/protein) contributed to the fall in Ks in malnutrition and endotoxemia, although reductions in the RNA concentration were most marked with protein deficiency and reductions in the KRNA dominated the response to the endotoxin. The changes in [GLN] and Ks were highly correlated as were [GLN] and both KRNA and the RNA concentration, and these relationships were unique to glutamine. These relationships could reflect sensitivity of glutamine transport and protein synthesis to the same regulatory influences, and the particular roles of insulin and T3 are discussed, as well as any direct influence of glutamine on protein synthesis.

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