scholarly journals Low-dose dexamethasone prevents endotoxaemia-induced muscle protein loss and impairment of carbohydrate oxidation in rat skeletal muscle

2010 ◽  
Vol 588 (8) ◽  
pp. 1333-1347 ◽  
Author(s):  
Hannah Crossland ◽  
Dumitru Constantin-Teodosiu ◽  
Paul L. Greenhaff ◽  
Sheila M. Gardiner
Keyword(s):  
Skeletal Muscle ◽  
Low Dose ◽  
Muscle Protein ◽  
Carbohydrate Oxidation ◽  
Rat Skeletal Muscle ◽  
Protein Loss

scholarly journals Posttranscriptional control of embryonic rat skeletal muscle protein synthesis. Control at the level of translation by endogenous RNA.

1988 ◽  
Vol 107 (3) ◽  
pp. 1085-1098 ◽  
Author(s):  
C R Vanderburg ◽  
M A Nathanson
Keyword(s):  
Skeletal Muscle ◽  
Cell Differentiation ◽  
Muscle Cell ◽  
Translational Control ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Skeletal Muscle Protein ◽  
Rat Skeletal Muscle ◽  
Total Rna ◽  
Muscle Cell Differentiation

The onset of muscle cell differentiation is associated with increased transcription of muscle-specific mRNA. Studies from this laboratory using 19-d embryonic rat skeletal muscle, suggest that additional, posttranscriptional controls regulate maturation of muscle tissue via a quantitative effect upon translation, and that the regulatory component may reside within the poly A- RNA pool (Nathanson, M.A., E.W. Bush, and C. Vanderburg. 1986. J. Biol. Chem. 261:1477-1486). To further characterize muscle cell translational control, embryonic and adult total RNA were separated into oligo(dT)cellulose-bound (poly A+) and -unbound (poly A-) pools. Unbound material was subjected to agarose gel electrophoresis to resolve constituents of varying molecular size and mechanically cut into five fractions. Material of each fraction was electroeluted and recovered by precipitation. Equivalent loads of total RNA from 19-20-d embryonic rat skeletal muscle exhibited a 40% translational inhibition in comparison to its adult counterpart. Inhibition was not due to decreased message abundance because embryonic, as well as adult muscle, contained equivalent proportions of poly A+ mRNA. An inhibition assay, based upon the translatability of adult RNA and its inhibition by embryonic poly A- RNA, confirmed that inhibition was associated with a 160-2,000-nt poly A- fraction. Studies on the chemical composition of this fraction confirmed its RNA composition, the absence of ribonucleoprotein, and that its activity was absent from similarly fractionated adult RNA. Rescue of inhibition could be accomplished by addition of extra lysate or mRNA; however, smaller proportions of lysate were required, suggesting a strong interaction of inhibitor and components of the translational apparatus. Additional studies demonstrated that the inhibitor acted at the level of initiation, in a dose-dependent fashion. The present studies confirm the existence of translational control in skeletal muscle and suggest that it operates at the embryonic to adult transition. A model of muscle cell differentiation, based upon transcriptional control at the myoblast level, followed by translational regulation at the level of the postmitotic myoblast and/or myotube, is proposed.

scholarly journals A potential role for Akt/FOXO signalling in both protein loss and the impairment of muscle carbohydrate oxidation during sepsis in rodent skeletal muscle

2008 ◽  
Vol 586 (22) ◽  
pp. 5589-5600 ◽  
Author(s):  
Hannah Crossland ◽  
Dumitru Constantin-Teodosiu ◽  
Sheila M. Gardiner ◽  
Despina Constantin ◽  
Paul L. Greenhaff
Keyword(s):  
Skeletal Muscle ◽  
Potential Role ◽  
Carbohydrate Oxidation ◽  
Protein Loss

Use of Growth Hormone and Insulin-like Growth Factor 1 for Treatment of Tissue Wasting in Catabolic Conditions

2000 ◽  
Vol 35 (2) ◽  
pp. 163-168
Author(s):  
Martin M. Zdanowicz
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Growth Factor ◽  
Burn Injury ◽  
Muscle Protein ◽  
Trauma Surgery ◽  
Insulin Like Growth Factor ◽  
Protein Loss ◽  
Body Tissues ◽  
Limited Effectiveness

Trauma, surgery, burn injury, sepsis, prolonged bed rest, cancer, and AIDS are examples of catabolic states that can lead to a significant loss of lean body tissues and skeletal muscle. The physiologic stresses associated with these catabolic conditions can impair immune function, alter drug response, and delay the recovery process. Although enhanced nutritional supplementation is a mainstay for treating tissue wasting in these conditions, it is of limited effectiveness in reversing skeletal muscle protein loss or enhancing anabolism in lean body tissues. The use of anabolic hormones such as Growth Hormone (GH) or Insulin-Like Growth Factor 1 (IGF-1) to limit lean body wasting and preserve muscle mass in these conditions has been widely investigated. This article was designed to give pharmacists and patient care professionals an overview of recent literature involving anabolic hormone treatment of tissue wasting. The use of these agents in the clinical setting may undergo significant expansion in the near future.

scholarly journals Effect of electrical stimulation-induced resistance exercise on mitochondrial fission and fusion proteins in rat skeletal muscle

2015 ◽  
Vol 40 (11) ◽  
pp. 1137-1142 ◽  
Author(s):  
Yu Kitaoka ◽  
Riki Ogasawara ◽  
Yuki Tamura ◽  
Satoshi Fujita ◽  
Hideo Hatta
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Resistance Exercise ◽  
Mitochondrial Function ◽  
Muscle Protein ◽  
Mitochondrial Dynamics ◽  
Muscle Protein Synthesis ◽  
Mitochondrial Fission ◽  
Dynamic Networks ◽  
Rat Skeletal Muscle

It is well known that resistance exercise increases muscle protein synthesis and muscle strength. However, little is known about the effect of resistance exercise on mitochondrial dynamics, which is coupled with mitochondrial function. In skeletal muscle, mitochondria exist as dynamic networks that are continuously remodeling through fusion and fission. The purpose of this study was to investigate the effect of acute and chronic resistance exercise, which induces muscle hypertrophy, on the expression of proteins related to mitochondrial dynamics in rat skeletal muscle. Resistance exercise consisted of maximum isometric contraction, which was induced by percutaneous electrical stimulation of the gastrocnemius muscle. Our results revealed no change in levels of proteins that regulate mitochondrial fission (Fis1 and Drp1) or fusion (Opa1, Mfn1, and Mfn2) over the 24-h period following acute resistance exercise. Phosphorylation of Drp1 at Ser616 was increased immediately after exercise (P < 0.01). Four weeks of resistance training (3 times/week) increased Mfn1 (P < 0.01), Mfn2 (P < 0.05), and Opa1 (P < 0.01) protein levels without altering mitochondrial oxidative phosphorylation proteins. These observations suggest that resistance exercise has little effect on mitochondrial biogenesis but alters the expression of proteins involved in mitochondrial fusion and fission, which may contribute to mitochondrial quality control and improved mitochondrial function.

Effect of flaxseed oil on muscle protein loss and carbohydrate oxidation impairment in a pig model after lipopolysaccharide challenge

2019 ◽  
Vol 123 (8) ◽  
pp. 859-869
Author(s):  
Ping Kang ◽  
Yang Wang ◽  
Xiangen Li ◽  
Zhicheng Wan ◽  
Xiuying Wang ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Pyruvate Dehydrogenase ◽  
Muscle Protein ◽  
Pyruvate Dehydrogenase Complex ◽  
Plasma Concentrations ◽  
Flaxseed Oil ◽  
Carbohydrate Oxidation ◽  
Pyruvate Dehydrogenase Kinase ◽  
Protein Loss ◽  
Lps Challenge

AbstractFlaxseed oil is rich in α-linolenic acid (ALA), which is the metabolic precursor of EPA and DHA. The present study investigated the effect of flaxseed oil supplementation on lipopolysaccharide (LPS)-induced muscle atrophy and carbohydrate oxidation impairment in a piglet model. Twenty-four weaned pigs were used in a 2 × 2 factorial experiment including dietary treatment (5 % maize oil v. 5 % flaxseed oil) and LPS challenge (saline v. LPS). On day 21 of treatment, the pigs were injected intraperitoneally with 100 μg/kg body weight LPS or sterile saline. At 4 h after injection, blood, gastrocnemius muscle and longissimus dorsi muscle were collected. Flaxseed oil supplementation increased ALA, EPA, total n-3 PUFA contents, protein:DNA ratio and pyruvate dehydrogenase complex quantity in muscles (P < 0·05). In addition, flaxseed oil reduced mRNA expression of toll-like receptor (TLR) 4 and nucleotide-binding oligomerisation domain protein (NOD) 2 and their downstream signalling molecules in muscles and decreased plasma concentrations of TNF-α, IL-6 and IL-8, and mRNA expression of TNF-α, IL-1β and IL-6 (P < 0·05). Moreover, flaxseed oil inclusion increased the ratios of phosphorylated protein kinase B (Akt) 1:total Akt1 and phosphorylated Forkhead box O (FOXO) 1:total FOXO1 and reduced mRNA expression of FOXO1, muscle RING finger (MuRF) 1 and pyruvate dehydrogenase kinase 4 in muscles (P < 0·05). These results suggest that flaxseed oil might have a positive effect on alleviating muscle protein loss and carbohydrates oxidation impairment induced by LPS challenge through regulation of the TLR4/NOD and Akt/FOXO signalling pathways.

A reexamination of the effect of exercise on rate of muscle protein degradation

2006 ◽  
Vol 263 (6) ◽  
pp. E1144-E1150 ◽  
Author(s):  
G. J. Kasperek ◽  
G. R. Conway ◽  
D. S. Krayeski ◽  
J. J. Lohne
Keyword(s):  
Skeletal Muscle ◽  
Protein Degradation ◽  
Total Protein ◽  
Food Restriction ◽  
Muscle Protein ◽  
Recovery Period ◽  
Lower Leg ◽  
Myofibrillar Protein ◽  
Rat Skeletal Muscle ◽  
Muscle Protein Degradation

The purpose of this study was to examine the effect of exercise on the rate of protein degradation in rat skeletal muscle. The rates of total and myofibrillar protein degradation were determined by the measurement of the rates of release of tyrosine and 3-methylhistidine, respectively, from the perfused single rat leg. This method measures the rate of protein degradation in the entire lower leg and does not suffer from the limitations inherent in methods that rely on urinary excretion. The rate of total protein degradation was increased by exercise and involved increased flux through the lysosomal pathway, while the breakdown of myofibrillar protein was unchanged. The changes in the rates of protein degradation during the recovery period were greatly influenced by energy intake. Again the rate of myofibrillar protein degradation was unchanged or slightly increased during the recovery period, after either level or downgrade running. Exercise did prevent the increase in the rate of total protein degradation caused by food restriction, which may have important implications in weight reduction diets.

scholarly journals The sedimentation of rat skeletal-muscle ribosomes. Effect of hydrocortisone, insulin and diet

1968 ◽  
Vol 106 (4) ◽  
pp. 913-919 ◽  
Author(s):  
V. R. Young ◽  
S. C. Chen ◽  
Jane Macdonald
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Sucrose Gradient ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Insulin Injection ◽  
Sedimentation Analysis ◽  
Rat Skeletal Muscle ◽  
Protein Free Diet ◽  
Post Mitochondrial Supernatant

1. The influence of hydrocortisone, insulin and diet on the size distribution of ribosomes in a post-mitochondrial supernatant prepared from rat skeletal muscle was studied by sedimentation analysis with a linear 15–40% (w/v) sucrose gradient. 2. Within 4hr. after the injection of 5mg. of hydrocortisone to well-nourished rats, a decrease in the yield per g. of muscle and proportion of total RNA due to polyribosomes was observed. Similar results were obtained in rats given a protein-free diet for 3 days before administration of the hormone. 3. Insulin injection increased the yield and proportion of polyribosomes within 2hr. and decreased the proportion of the lighter ribosomal aggregates. Similar results were noted in rats given a protein-free diet for 3 days before injection. A protein-free diet given for 3 days decreased the yield and proportion of polyribosomes. Insulin did not increase the yield of polyribosomes if rats were starved for 52hr. before injection, but decreased the yield and proportion of the lighter ribosome species. 4. A 52hr. period of starvation or 2,4-dinitrophenol (15mg./kg. body wt.) given 1hr. before the rats were killed resulted in a decreased yield and proportion of polyribosomes, and, within 6hr. of re-feeding the rats with protein-free diets, an increased concentration of polyribosomes was noted. 5. The effects of a protein-free diet, hydrocortisone and insulin on the sedimentation of muscle ribosomes were found to be in accord with their net effects on muscle protein synthesis.

scholarly journals Ectopic expression of eIF2Bε in rat skeletal muscle rescues the sepsis-induced reduction in guanine nucleotide exchange activity and protein synthesis

2010 ◽  
Vol 299 (2) ◽  
pp. E241-E248 ◽  
Author(s):  
Alexander P. Tuckow ◽  
Thomas C. Vary ◽  
Scot R. Kimball ◽  
Leonard S. Jefferson
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Ectopic Expression ◽  
Initiation Factor ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Rat Skeletal Muscle ◽  
Guanine Nucleotide Exchange

Eukaryotic initiation factor 2B (eIF2B) is a guanine nucleotide exchange factor (GEF) whose activity is both tightly regulated and rate-controlling with regard to global rates of protein synthesis. Skeletal muscle eIF2B activity and expression of its catalytic ε-subunit (eIF2Bε) have been implicated as potential contributors to the altered rates of protein synthesis in a number of physiological conditions and experimental models. The objective of this study was to directly examine the effects of exogenously expressed eIF2Bε in vivo on GEF activity and protein synthetic rates in rat skeletal muscle. A plasmid encoding FLAG-eIF2Bε was transfected into the tibialis anterior (TA) of one leg, while the contralateral TA received a control plasmid. Ectopic expression of eIF2Bε resulted in increased GEF activity in TA homogenates of healthy rats, demonstrating that the expressed protein was catalytically active. In an effort to restore a deficit in eIF2B activity, we utilized an established model of chronic sepsis in which skeletal muscle eIF2B activity is known to be impaired. Ectopic expression of eIF2Bε in the TA rescued the sepsis-induced deficit in GEF activity and muscle protein synthesis. The results demonstrate that modulation of eIF2Bε expression may be sufficient to correct deficits in skeletal muscle protein synthesis associated with sepsis and other muscle-wasting conditions.

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