Depression of protein synthesis after ischaemia in rat skeletal muscle unassociated with energy or redox status

1985 ◽  
Vol 13 (2) ◽  
pp. 382-382
Author(s):  
P. A. MACLENNAN ◽  
M. J. RENNIE
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Redox Status ◽  
Rat Skeletal Muscle

Ceramide down‐regulates System A amino acid transport and protein synthesis in rat skeletal muscle cells

2004 ◽  
Vol 19 (3) ◽  
pp. 1-24 ◽  
Author(s):  
Russell Hyde ◽  
Eric Hajduch ◽  
Darren J. Powell ◽  
Peter M. Taylor ◽  
Harinder S. Hundal
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Acid Transport ◽  
Rat Skeletal Muscle ◽  
System A

scholarly journals Downregulation of AMPK Accompanies Leucine- and Glucose-Induced Increases in Protein Synthesis and Insulin Resistance in Rat Skeletal Muscle

Diabetes ◽  
2010 ◽  
Vol 59 (10) ◽  
pp. 2426-2434 ◽  
Author(s):  
Asish K. Saha ◽  
X. Julia Xu ◽  
Ebony Lawson ◽  
Rosangela Deoliveira ◽  
Amanda E. Brandon ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Rat Skeletal Muscle

Protein turnover in rat skeletal muscle: effects of hypophysectomy and growth hormone.

1978 ◽  
Vol 234 (1) ◽  
pp. E38 ◽  
Author(s):  
K E Flaim ◽  
J B Li ◽  
L S Jefferson
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Gastrocnemius Muscle ◽  
Growth Hormone Treatment ◽  
Hormone Replacement ◽  
Hormone Treatment ◽  
Rat Skeletal Muscle

The role of growth hormone in regulating protein turnover was examined in a perfused preparation of rat skeletal muscle. The perfused muscle maintained in vivo levels of ATP and creatine phosphate and exhibited constant rates of oxygen consumption and protein synthesis. Hypophysectomy reduced the rate of protein synthesis, the concentration of RNA, and the efficiency of protein synthesis in gastrocnemius muscle to 30, 46, and 66 percent of normal, respectively. In vivo treatment of hypophysectomized (hypox) rats with bovine growth hormone (250 microgram/day for 5 days) resulted in small increases in protein synthesis and RNA, whereas synthesis/RNA was returned to near normal. Elevation of ribosomal subunits in psoas muscle indicated an inhibition of peptide-chain initiation in hypox rats that was reversed by in vivo growth hormone treatment. Thus, hypox rats exhibited both a decreased capacity and a decreased efficiency of protein synthesis. Growth hormone replacement primarily increased efficiency of protein synthesis. The rate of protein degradation and the activity of cathepsin D in gastrocnemius muscle were decreased by hypophysectomy. Growth hormone treatment had no significant effect on degradation.

Role of eIF4E in stimulation of protein synthesis by IGF-I in perfused rat skeletal muscle

2000 ◽  
Vol 278 (1) ◽  
pp. E58-E64 ◽  
Author(s):  
Thomas C. Vary ◽  
Leonard S. Jefferson ◽  
Scot R. Kimball
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Initiation Factor ◽  
Translational Efficiency ◽  
Rat Skeletal Muscle ◽  
Phosphorylation State ◽  
Factor I ◽  
Igf I ◽  
Stimulation Of

Insulin-like growth factor I (IGF-I) promotes anabolism by stimulating protein synthesis in skeletal muscle. In the present study, we have examined mechanisms by which IGF-I stimulates protein synthesis in skeletal muscle with a perfused rat hindlimb preparation. IGF-I (10 nM) stimulated protein synthesis over 2.7-fold. Total RNA content was unaffected, but translational efficiency was increased by IGF-I. We next examined the effect of IGF-I on eukaryotic initiation factor (eIF) 4E as a mechanism regulating translation initiation. IGF-I did not alter either the amount of eIF4E associated with the eIF4E binding protein 4E-BP1 or the phosphorylation state of 4E-BP1. Likewise, the phosphorylation state of eIF4E was unaltered by IGF-I. In contrast, the amount of eIF4E bound to eIF4G was increased threefold by IGF-I. We conclude that IGF-I regulates protein synthesis in skeletal muscle by enhancing formation of the active eIF4E ⋅ eIF4G complex.

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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