Stimulation of C14-histidine incorporation into protein of isolated diaphragm by nonutilized sugars

1960 ◽  
Vol 198 (1) ◽  
pp. 57-59 ◽  
Author(s):  
Ira G. Wool
Keyword(s):  
Protein Synthesis ◽  
Glucose Concentration ◽  
Protein Metabolism ◽  
Incubation Medium ◽  
Muscle Protein ◽  
Positive Influence ◽  
Effect Of Glucose ◽  
Stimulation Of

The effect of various sugars on protein synthesis was studied by measuring the incorporation of C14-histidine into the protein of the isolated diaphragm. In diaphragms from rats fasted 48 hours, histidine-2-C14 incorporation into muscle protein is directly proportional to the glucose concentration in the incubation medium over the range 0–600 mg %. The ability of other sugars to reproduce this effect of glucose on C14-histidine incorporation into diaphragm protein was tested. The following were found to be as effective as glucose: d-mannose; d-xylose; d-ribose; l-sorbose. The following were without effect: d-galactose; d-fructose; 3-methyl glucose; d-arabinose; l-arabinose; l-xylose. Only 2-deoxy-d-glucose was inhibitory. The results indicate that sugars not appreciably utilized by muscle (i.e. d-xylose, d-ribose and l-sorbose) can increase protein synthesis. The findings do not support the theory that the positive influence of carbohydrate on protein metabolism derives solely from its ability to increase the energy available for protein synthesis.

Incorporation of C14-amino acids into protein of isolated diaphragms: an effect of insulin independent of glucose entry

1959 ◽  
Vol 196 (5) ◽  
pp. 961-964 ◽  
Author(s):  
Ira G. Wool ◽  
M. E. Krahl
Keyword(s):  
Amino Acids ◽  
Glucose Concentration ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Rat Diaphragm ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Effect Of Glucose ◽  
Positive Effect ◽  
Isolated Rat

The effect of glucose concentration and insulin on protein synthesis was investigated using the isolated rat diaphragm and C14-labeled amino acids. When the donor rat has been well fed, the incorporation of histidine-2-C14, lysine-2-C14, phenylalanine-3-C14, and alanine-1-C14 into muscle protein is uninfluenced by glucose concentration in the medium over the range 0–600 mg %. Insulin leads to an increase in C14-amino acid incorporation into muscle protein in the absence of glucose in the medium. This positive effect of insulin in the absence of added glucose is still observed when the diaphragms are pre-incubated for 2 hours prior to adding insulin. These findings suggest an effect of insulin on protein metabolism independent of its action in promoting glucose entry.

scholarly journals Comprehensive assessment of post-prandial protein handling by the application of intrinsically labelled protein in vivo in human subjects

2021 ◽  
pp. 1-9
Author(s):  
Jorn Trommelen ◽  
Andrew M. Holwerda ◽  
Philippe J. M. Pinckaers ◽  
Luc J. C. van Loon
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Stable Isotope ◽  
Dietary Protein ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Human Subjects ◽  
Whole Body ◽  
Body Protein

All human tissues are in a constant state of remodelling, regulated by the balance between tissue protein synthesis and breakdown rates. It has been well-established that protein ingestion stimulates skeletal muscle and whole-body protein synthesis. Stable isotope-labelled amino acid methodologies are commonly applied to assess the various aspects of protein metabolism in vivo in human subjects. However, to achieve a more comprehensive assessment of post-prandial protein handling in vivo in human subjects, intravenous stable isotope-labelled amino acid infusions can be combined with the ingestion of intrinsically labelled protein and the collection of blood and muscle tissue samples. The combined application of ingesting intrinsically labelled protein with continuous intravenous stable isotope-labelled amino acid infusion allows the simultaneous assessment of protein digestion and amino acid absorption kinetics (e.g. release of dietary protein-derived amino acids into the circulation), whole-body protein metabolism (whole-body protein synthesis, breakdown and oxidation rates and net protein balance) and skeletal muscle metabolism (muscle protein fractional synthesis rates and dietary protein-derived amino acid incorporation into muscle protein). The purpose of this review is to provide an overview of the various aspects of post-prandial protein handling and metabolism with a focus on insights obtained from studies that have applied intrinsically labelled protein under a variety of conditions in different populations.

Role of insulin and IGF-I in activation of muscle protein synthesis after oral feeding

1996 ◽  
Vol 270 (4) ◽  
pp. E614-E620 ◽  
Author(s):  
E. Svanberg ◽  
H. Zachrisson ◽  
C. Ohlsson ◽  
B. M. Iresjo ◽  
K. G. Lundholm
Keyword(s):  
Protein Synthesis ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Oral Feeding ◽  
Myofibrillar Proteins ◽  
Diabetic Mice ◽  
Igf I ◽  
Stimulation Of

The aim was to evaluate the role of insulin and insulin-like growth factor I (IGF-I) in activation of muscle protein synthesis after oral feeding. Synthesis rate of globular and myofibrillar proteins in muscle tissue was quantified by a flooding dose of radioactive phenylalanine. Muscle tissue expression of IGF-I mRNA was measured. Normal (C57 Bl) and diabetic mice (type I and type II) were subjected to an overnight fast (18 h) with subsequent refeeding procedures for 3 h with either oral chow intake or provision of insulin, IGF-I, glucose, and amino acids. Anti-insulin and anti-IGF-I were provided intraperitoneally before oral refeeding in some experiments. An overnight fast reduced synthesis of both globular (38 +/- 3%) and myofibrillar proteins (54 +/- 3%) in skeletal muscles, which was reversed by oral refeeding. Muscle protein synthesis, after starvation/ refeeding, was proportional and similar to changes in skeletal muscle IGF-I mRNA expression. Diabetic mice responded quantitatively similarly to starvation/refeeding in muscle protein synthesis compared with normal mice (C57 Bl). Both anti-insulin and anti-IGF-I attenuated significantly the stimulation of muscle protein synthesis in response to oral feeding, whereas exogenous provision of either insulin or IGF-I to overnight-starved and freely fed mice did not clearly stimulate protein synthesis in skeletal muscles. Our results support the suggestion that insulin and IGF-I either induce or facilitate the protein synthesis machinery in skeletal muscles rather than exerting a true stimulation of the biosynthetic process during feeding.

Effects of glucose, pyruvate, lactate, and amino acids on muscle protein synthesis

1982 ◽  
Vol 242 (3) ◽  
pp. E184-E192 ◽  
Author(s):  
M. P. Hedden ◽  
M. G. Buse
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Creatine Phosphate ◽  
Serum Amino Acids ◽  
14Co2 Production ◽  
Beta Hydroxybutyrate ◽  
Free Media ◽  
Effect Of Glucose

Protein synthesis was measured in rat diaphragms incubated with serum amino acids + 0.35 mM L-[2,6-3H]tyrosine and different energy-yielding substrates. Muscles incubated with 5.5 mM glucose (with or without actinomycin D) synthesized more protein than those incubated with 11 mM pyruvate or 11 mM lactate. Tissue ATP decreased during incubation with lactate, but pyruvate maintained ATP, ADP, and creatine phosphate as well as glucose. Glucose 6-phosphate decreased in muscles incubated in glucose-free media. 14CO2 production from substrates was [1-14C]pyruvate greater than [1-14C]lactate greater than [3,4-14C]glucose. Intracellular lactate/pyruvate was measured to assess cytoplasmic free NADH/NAD+; the effect of different media on these ratios was lactate greater than glucose = lactate + pyruvate greater than pyruvate + glucose greater than pyruvate. Lactate + pyruvate (8.8 + 2.2 mM) supported protein synthesis better than pyruvate and as well as glucose. Adding glucose to pyruvate accelerated protein synthesis and increased NADH/NAD+. Iodoacetate (0.1 mM) inhibited glycolytic NAD reduction and abolished the stimulatory effect of glucose on protein synthesis in the presence of pyruvate. Supplementation of pyruvate media with 1 mM leucine or isoleucine stimulated protein synthesis, but beta-hydroxybutyrate, malate, alpha-ketoisocaproate, and all other amino acids were ineffective. The cytoplasmic redox potential may act as a translational modulator of protein synthesis in skeletal muscle.

Pentoxifylline decreases body weight loss and muscle protein wasting characteristics of sepsis

1993 ◽  
Vol 265 (4) ◽  
pp. E660-E666 ◽  
Author(s):  
D. Breuille ◽  
M. C. Farge ◽  
F. Rose ◽  
M. Arnal ◽  
D. Attaix ◽  
...  
Keyword(s):  
Body Weight ◽  
Protein Synthesis ◽  
Acute Phase ◽  
Protein Metabolism ◽  
Muscle Wasting ◽  
Acute Phase Protein ◽  
Muscle Protein ◽  
Liver Protein ◽  
Phase Protein

Sepsis induces metabolic disorders that include loss of body weight, muscle wasting, and acute-phase protein synthesis in liver. Cytokines are generally recognized as active mediators of these disorders, and the implication of tumor necrosis factor (TNF) has been frequently discussed in the recent past. However, the identity of the active agent in alterations of protein metabolism is still controversial. To improve our understanding of the role of cytokines in mediating muscle wasting observed in sepsis, we investigated muscle and liver protein metabolism in the following three groups of rats: infected control rats (INF-C); infected rats pretreated with pentoxifylline (PTX-INF), which is a potent inhibitor of TNF secretion; and pair-fed rats for the PTX-INF group pretreated with pentoxifylline. Pentoxifylline nearly completely suppressed TNF secretion but did not influence the transient fall in rectal temperature, the decreased hematocrit, and the increased liver protein mass and synthesis observed in INF-C rats. Pentoxifylline decreased the anorexia, the loss of body weight and muscle protein observed in INF-C animals, and partially prevented the decrease in muscle protein synthesis induced by infection. The overall data indicate that pentoxifylline is an effective agent in mitigating the characteristic muscle protein wasting induced by sepsis and confirm the limited role of TNF in the mediation of the acute-phase protein synthesis. Our results suggest a probable implication of TNF in the regulation of protein balance in muscle but do not allow discarding possible implication of other mediators that would be inhibited by pentoxifylline.

scholarly journals Stimulation of Muscle Protein Synthesis by Prolonged Parenteral Infusion of Leucine Is Dependent on Amino Acid Availability in Neonatal Pigs

2009 ◽  
Vol 140 (2) ◽  
pp. 264-270 ◽  
Author(s):  
Fiona A. Wilson ◽  
Agus Suryawan ◽  
Maria C. Gazzaneo ◽  
Renán A. Orellana ◽  
Hanh V. Nguyen ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Neonatal Pigs ◽  
Amino Acid Availability ◽  
Stimulation Of

scholarly journals Effects of acute oral feeding on protein metabolism and muscle protein synthesis in individuals with cancer

Nutrition ◽  
2019 ◽  
Vol 67-68 ◽  
pp. 110531 ◽  
Author(s):  
Barbara S. van der Meij ◽  
Lynette M. De Groot ◽  
Nicolaas E.P. Deutz ◽  
Mariëlle P.K.J. Engelen
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Oral Feeding

Prevention of skeletal muscle catabolism in sepsis does not impair visceral protein metabolism

1996 ◽  
Vol 270 (4) ◽  
pp. E621-E626 ◽  
Author(s):  
R. N. Cooney ◽  
E. Owens ◽  
D. Slaymaker ◽  
T. C. Vary
Keyword(s):  
Protein Synthesis ◽  
Small Intestine ◽  
Protein Content ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Interleukin 1 ◽  
Intestinal Protein ◽  
Muscle Catabolism ◽  
Induced Changes ◽  
Septic Insult

We investigated whether the preservation of gastrocnemius proteins by interleukin-1 receptor antagonist (IL-1ra) during sepsis altered protein metabolism in visceral tissues. Sepsis was induced by creation of an abdominal abscess followed by infusion of saline of IL-1ra. Five days later, the tissue protein content and rate of protein synthesis were measured. IL-1ra did not significantly alter hepatic protein metabolism in septic or control animals. In kidney, the protein content and rate of protein synthesis were both decreased by sepsis and significantly ameliorated by the infusion of IL-1ra. Sepsis decreased the rate of protein synthesis in the small intestine. IL-1ra increased intestinal protein synthesis in both control and septic animals; however, the effects were localized to the seromuscular layer. The preservation of muscle protein by IL-1ra in sepsis did not adversely affect protein synthesis in any of the visceral tissues examined. IL-1 appears to mediate the sepsis-induced changes in protein synthesis in kidney and small intestine but not in liver or spleen. Protein synthesis in each visceral organ responds differently to the septic insult and modulation of IL-1 bioactivity.

Sign in / Sign up

Export Citation Format

Share Document