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.

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.

Relationship between glutamine concentration and protein synthesis in rat skeletal muscle

1988 ◽  
Vol 255 (2) ◽  
pp. E166-E172 ◽  
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.

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.

Regulation of hepatic protein synthesis in chronic inflammation and sepsis

1992 ◽  
Vol 262 (2) ◽  
pp. C445-C452 ◽  
Author(s):  
T. C. Vary ◽  
S. R. Kimball
Keyword(s):  
Protein Synthesis ◽  
Sterile Inflammation ◽  
Chain Elongation ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Translational Efficiency ◽  
Liver Protein ◽  
Ribosomal Subunits ◽  
Hepatic Protein Synthesis

The regulation of protein synthesis was determined in livers from control, sterile inflammatory, and septic animals. Total liver protein was increased in both sterile inflammation and sepsis. The rate of protein synthesis in vivo was measured by the incorporation of [3H]phenylalanine into liver proteins in a chronic (5 day) intra-abdominal abscess model. Both sterile inflammation and sepsis increased total hepatic protein synthesis approximately twofold. Perfused liver studies demonstrated that the increased protein synthesis rate in vivo resulted from a stimulation in the synthesis of both secreted and nonsecreted proteins. The total hepatic RNA content was increased 40% only in sterile inflammation, whereas the translational efficiency was increased twofold only in sepsis. The increase in translational efficiency was accompanied by decreases in the amount of free 40S and 60S ribosomal subunits in sepsis. Rates of peptide-chain elongation in vivo were increased 40% in both sterile inflammation and sepsis. These results demonstrate that sepsis induces changes in the regulation of hepatic protein synthesis that are independent of the general inflammatory response. In sterile inflammation, the increase in protein synthesis occurs by a combination of increased capacity and translational efficiency, while in sepsis, the mechanism responsible for accelerated protein synthesis is an increased translational efficiency.

Elevated plasma lactate levels via exogenous lactate infusion do not alter resistance exercise-induced signaling or protein synthesis in human skeletal muscle

2020 ◽  
Vol 319 (4) ◽  
pp. E792-E804
Author(s):  
Rasmus Liegnell ◽  
William Apró ◽  
Sebastian Danielsson ◽  
Björn Ekblom ◽  
Gerrit van Hall ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Blood Lactate ◽  
Intracellular Signaling ◽  
Recovery Period ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Lactate Levels ◽  
The Impact

Lactate has been implicated as a potential signaling molecule. In myotubes, lactate incubation increases mechanistic target of rapamycin complex 1 (mTORC1)- and ERK-signaling and induces hypertrophy, indicating that lactate could be a mediator of muscle adaptations to resistance exercise. However, the potential signaling properties of lactate, at rest or with exercise, have not been explored in human tissue. In a crossover design study, 8 men and 8 women performed one-legged resistance exercise while receiving venous infusion of saline or sodium lactate. Blood was sampled repeatedly, and muscle biopsies were collected at rest and at 0, 90, and 180 min and 24 h after exercise. The primary outcomes examined were intracellular signaling, fractional protein synthesis rate (FSR), and blood/muscle levels of lactate and pH. Postexercise blood lactate concentrations were 130% higher in the Lactate trial (3.0 vs. 7.0 mmol/L, P < 0.001), whereas muscle levels were only marginally higher (27 vs. 32 mmol/kg dry wt, P = 0.003) compared with the Saline trial. Postexercise blood pH was higher in the Lactate trial (7.34 vs. 7.44, P < 0.001), with no differences in intramuscular pH. Exercise increased the phosphorylation of mTORS2448 (∼40%), S6K1T389 (∼3-fold), and p44T202/T204 (∼80%) during recovery, without any differences between trials. FSR over the 24-h recovery period did not differ between the Saline (0.067%/h) and Lactate (0.062%/h) trials. This study does not support the hypothesis that blood lactate levels can modulate anabolic signaling in contracted human muscle. Further in vivo research investigating the impact of exercised versus rested muscle and the role of intramuscular lactate is needed to elucidate its potential signaling properties.

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.

PHENYLALANINE METABOLISM IN SHEEP INFUSED WITH GLUCOSE PLUS INSULIN. II. EFFECTS ON IN VIVO AND IN VITRO PROTEIN SYNTHESIS AND RELATED ENERGY EXPENDITURES

1988 ◽  
Vol 68 (3) ◽  
pp. 721-730 ◽  
Author(s):  
RICHARD J. EARLY ◽  
BRIAN W. McBRIDE ◽  
RONALD O. BALL
Keyword(s):  
Protein Synthesis ◽  
Gastrocnemius Muscle ◽  
Specific Radioactivity ◽  
Intercostal Muscle ◽  
Energy Expenditures ◽  
Phenylalanine Metabolism ◽  
Arterial Plasma ◽  
Vitro Protein

In vivo fractional rates of protein synthesis (FSR), based on both intracellular fluid (ICF) and arterial plasma specific radioactivity (SRA), were determined for the external intercostal muscle (EIC), gastrocnemius muscle, liver and kidneys of growing sheep during infusions of either saline or glucose (2 g h−1) plus insulin (1.2 U h−1; G+I). In vitro FSR and energy expenditures associated with protein synthesis (cycloheximide-sensitive respiration) and Na+, K+ transport (ouabain-sensitive respiration) were also determined in EIC muscle. In vivo FSR based on ICF SRA in muscle were not significantly different between G+I and S infused sheep (5.2 vs. 4.2% d−1 and 5.0 vs. 3.2% d−1 for EIC and gastrocnemius, respectively). In vivo FSR in the liver (54 vs. 61% d−1) and kidneys (38 vs. 55% d−1) were also not significantly different between G+I versus S infused sheep. Based on plasma SRA, FSR in all tissues were unaffected by treatments and were less (P < 0.05) than those calculated from ICF SRA. In vitro FSR and the energy expenditures associated with protein synthesis and Na+, K+ transport were not affected by G+I infusions. The average in vitro FSR in isolated EIC muscle (2.7% d−1) was 53% and 81% of the average in vivo FSR calculated from ICF and plasma SRA, respectively. Compared to data reported for nonruminants, these data suggest that rates of protein synthesis and energy expenditures associated with protein synthesis in ruminants are less influenced by insulin and glucose. Key words: Sheep, protein synthesis, insulin, glucose, Na+, K+ transport

scholarly journals Comparison of protein-synthesis rate of alveolar macrophages in vivo and in vitro

1984 ◽  
Vol 217 (3) ◽  
pp. 761-765 ◽  
Author(s):  
M H Oliver ◽  
P J Cole ◽  
G J Laurent
Keyword(s):  
Protein Synthesis ◽  
Alveolar Macrophages ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Novel Method

This paper describes and validates a novel method for measuring rates of protein synthesis of rabbit alveolar macrophages in vivo. A rate of 9.3%/day was obtained, compared with 48.9%/day measured in vitro. This study suggests that the procedures involved in the isolation of alveolar macrophages for study in vitro may themselves activate the cell.

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