A reexamination of the effects of creatine on muscle protein synthesis in tissue culture.

Experiments designed to test the hypothesis that intracellular creatine level regulates the synthesis of muscle specific proteins have failed to demonstrate any creatine regulatory effect. Manipulation of the extracellular creatine in culture medium over a 5,700-fold range (1.3-7.4 mM) was successful in altering intracellular total creatine by only a factor of 20 (1.4-42 mg creatine/mg protein), an indication that muscle cells are able to regulate intracellular creatine levels over a wide range of external creatine concentrations. Alterations of cell creatine had no effect on either total protein synthesis or synthesis of myosin heavy chain. Methods were perfected to measure total creatine, and incorporation of [3H]leucine into total protein and purified myosin heavy chain from the same culture dish to avoid the possibility of variation between dishes. The creatine analog 1-carboxymethyl-2-iminohexahydropyrimidine (CMIP) previously reported to stimulate myosin synthesis in culture was found to depress creatine accumulation by cells and depressed total protein synthesis and synthesis of myosin heavy chain. This inhibitory action of CMIP is consistent with the reported competitive inhibition of creatine kinase and presumed interference with energy metabolism.

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SPECIFICITY OF CREATINE IN THE CONTROL OF MUSCLE PROTEIN SYNTHESIS

The Journal of Cell Biology ◽

10.1083/jcb.62.1.145 ◽

1974 ◽

Vol 62 (1) ◽

pp. 145-151 ◽

Cited By ~ 55

Author(s):

Joanne S. Ingwall ◽

Cynthia D. Weiner ◽

Manuel F. Morales ◽

Elaine Davis ◽

Frank E. Stockdale

Keyword(s):

Skeletal Muscle ◽

Amino Acids ◽

Protein Synthesis ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Muscle Creatine ◽

Embryonic Muscle ◽

Chain Synthesis

This study provides additional evidence that creatine, an end product of contraction unique to muscle, is involved in the control of muscle protein synthesis. Creatine is shown to stimulate selectively the rate of synthesis of two major contractile proteins, actin and myosin heavy chain, in cultures of differentiating skeletal muscle. Creatine affects only the rate of synthesis and not the rate of degradation. Several creatine analogs are as effective as creatine in stimulating muscle protein synthesis, creatinine and amino acids such as arginine and glycine are not. Creatine stimulates myosin heavy chain synthesis twofold in cultures of embryonic muscle grown in either normal or dialyzed media.

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Effects of acute creatine monohydrate supplementation on leucine kinetics and mixed-muscle protein synthesis

Journal of Applied Physiology ◽

10.1152/jappl.2001.91.3.1041 ◽

2001 ◽

Vol 91 (3) ◽

pp. 1041-1047 ◽

Cited By ~ 134

Author(s):

G. Parise ◽

S. Mihic ◽

D. MacLennan ◽

K. E. Yarasheski ◽

M. A. Tarnopolsky

Keyword(s):

Protein Synthesis ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Fat Free Mass ◽

Whole Body ◽

Synthetic Rate ◽

Fractional Synthetic Rate ◽

Before And After ◽

Total Creatine ◽

Plasma Leucine

Creatine monohydrate (CrM) supplementation during resistance exercise training results in a greater increase in strength and fat-free mass than placebo. Whether this is solely due to an increase in intracellular water or whether there may be alterations in protein turnover is not clear at this point. We examined the effects of CrM supplementation on indexes of protein metabolism in young healthy men ( n = 13) and women ( n = 14). Subjects were randomly allocated to CrM (20 g/day for 5 days followed by 5 g/day for 3–4 days) or placebo (glucose polymers) and tested before and after the supplementation period under rigorous dietary and exercise controls. Muscle phosphocreatine, creatine, and total creatine were measured before and after supplementation. A primed-continuous intravenous infusion of l-[1-13C]leucine and mass spectrometry were used to measure mixed-muscle protein fractional synthetic rate and indexes of whole body leucine metabolism (nonoxidative leucine disposal), leucine oxidation, and plasma leucine rate of appearance. CrM supplementation increased muscle total creatine (+13.1%, P < 0.05) with a trend toward an increase in phosphocreatine (+8.8%, P = 0.09). CrM supplementation did not increase muscle fractional synthetic rate but reduced leucine oxidation (−19.6%) and plasma leucine rate of appearance (−7.5%, P < 0.05) in men, but not in women. CrM did not increase total body mass or fat-free mass. We conclude that short-term CrM supplementation may have anticatabolic actions in some proteins (in men), but CrM does not increase whole body or mixed-muscle protein synthesis.

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Glutamine prevents downregulation of myosin heavy chain synthesis and muscle atrophy from glucocorticoids

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1995.268.4.e730 ◽

1995 ◽

Vol 268 (4) ◽

pp. E730-E734 ◽

Cited By ~ 7

Author(s):

R. C. Hickson ◽

S. M. Czerwinski ◽

L. E. Wegrzyn

Keyword(s):

Protein Synthesis ◽

Myosin Heavy Chain ◽

Muscle Mass ◽

Muscle Atrophy ◽

Heavy Chain ◽

Total Protein ◽

Female Rats ◽

Glucocorticoid Treatment ◽

Precursor Pool ◽

Chain Synthesis

The aims of this study were to determine whether glutamine infusion prevents the decline in protein synthesis and muscle wasting associated with repeated glucocorticoid treatment. Hormone (cortisol acetate, 100 mg.kg body wt-1.day-1) and vehicle (carboxymethyl cellulose)-treated female rats were infused with either saline or glutamine (240 mM, 0.75 ml/h) for a 7-day period. Glutamine infusion attenuated the decline of plantaris muscle glutamine concentration (3.0 +/- 0.2 vs. 2.3 +/- 0.2 mumol/g) and prevented > 70% of the total muscle mass losses due to the glucocorticoid injections. Fractional synthesis rates of myosin heavy chain (MHC) and total protein were determined after constant [3H]leucine infusion from the leucyl-tRNA precursor pool, which was similar in all groups (range 4.8 +/- 0.5 to 6.3 +/- 0.4 disintegrations.min-1.pmol-1). MHC synthesis rates (%/day) in plantaris muscles were reduced to approximately 40% of controls (4.2/9.4). Although glutamine had no effect on MHC synthesis in vehicle-treated animals (10.1/9.4), it prevented 50% (7.6/4.2) of the hormone-induced decline in MHC synthesis rates. The same results were obtained with total protein synthesis measurements. Changes in muscle mass did not appear related to estimates of protein breakdown. In conclusion, these data show that glutamine infusion is effective therapy in counteracting glucocorticoid-induced muscle atrophy. Atrophy attenuation appears related to maintaining muscle glutamine levels, which in turn may limit the glucocorticoid-mediated downregulation of MHC synthesis.

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Potato Protein Isolate Stimulates Muscle Protein Synthesis at Rest and with Resistance Exercise in Young Women

Nutrients ◽

10.3390/nu12051235 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1235 ◽

Cited By ~ 4

Author(s):

Sara Y. Oikawa ◽

Ravninder Bahniwal ◽

Tanya M. Holloway ◽

Changhyun Lim ◽

Jonathan C. McLeod ◽

...

Keyword(s):

Protein Synthesis ◽

Resistance Exercise ◽

Young Women ◽

Total Protein ◽

Protein Intake ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Control Diet ◽

Potato Protein ◽

Opposite Limb

Skeletal muscle myofibrillar protein synthesis (MPS) increases in response to protein feeding and to resistance exercise (RE), where each stimuli acts synergistically when combined. The efficacy of plant proteins such as potato protein (PP) isolate to stimulate MPS is unknown. We aimed to determine the effects of PP ingestion on daily MPS with and without RE in healthy women. In a single blind, parallel-group design, 24 young women (21 ± 3 years, n = 12/group) consumed a weight-maintaining baseline diet containing 0.8 g/kg/d of protein before being randomized to consume either 25 g of PP twice daily (1.6 g/kg/d total protein) or a control diet (CON) (0.8 g/kg/d total protein) for 2 wks. Unilateral RE (~30% of maximal strength to failure) was performed thrice weekly with the opposite limb serving as a non-exercised control (Rest). MPS was measured by deuterated water ingestion at baseline, following supplementation (Rest), and following supplementation + RE (Exercise). Ingestion of PP stimulated MPS by 0.14 ± 0.09 %/d at Rest, and by 0.32 ± 0.14 %/d in the Exercise limb. MPS was significantly elevated by 0.20 ± 0.11 %/d in the Exercise limb in CON (p = 0.008). Consuming PP to increase protein intake to levels twice the recommended dietary allowance for protein augmented rates of MPS. Performance of RE stimulated MPS regardless of protein intake. PP is a high-quality, plant-based protein supplement that augments MPS at rest and following RE in healthy young women.

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miR-23b-3p acts as a counter-response against skeletal muscle atrophy

Journal of Endocrinology ◽

10.1530/joe-19-0425 ◽

2020 ◽

Vol 244 (3) ◽

pp. 535-547 ◽

Cited By ~ 1

Author(s):

Takuro Okamura ◽

Yoshitaka Hashimoto ◽

Takafumi Osaka ◽

Takafumi Senmaru ◽

Takuya Fukuda ◽

...

Keyword(s):

Type 2 Diabetes ◽

Protein Synthesis ◽

Glucose Uptake ◽

Myosin Heavy Chain ◽

Muscle Atrophy ◽

Heavy Chain ◽

Muscle Protein ◽

Skeletal Muscle Atrophy ◽

C2c12 Myotube

To investigate the role of microRNA (miRNA) in muscle atrophy, we performed microarray analysis of miRNA expression in skeletal muscles of Sham, orchiectomized (ORX) mice, and ORX mice treated with androgen and identified that the expression of miR-23b-3p in ORX mice was significantly higher than that in Sham mice (P = 0.007); however, miR-23b-3p expression in ORX mice treated with androgen was lower (P = 0.001). We also investigated the mechanism by which overexpression or knockdown of miR-23b-3p influences the expression of myosin heavy chain, muscle protein synthesis, ATP activity, and glucose uptake in C2C12 myotube cells. Moreover, we examined the serum miR-23b-3p levels among male subjects with type 2 diabetes and whether the serum miR-23b-3p levels could be a biomarker for muscle atrophy. The overexpression of miR-23b-3p in C2C12 myotube cells significantly upregulated the expression of myosin heavy chain, protein synthesis, ATP activity, and glucose uptake. Reporter assays raised a possible direct post-transcriptional regulation involving miR-23b-3p and the 3′-UTR of PTEN mRNA. Among subjects with type 2 diabetes, serum miR-23b-3p levels in the subjects with decreased muscle mass were significantly higher compared to the levels in the subjects without. Our results indicate that miR-23b-3p downregulates the expression of PTEN in myotube cells and induces the growth of myosin heavy chain. In addition, the serum level of miR-23b-3p can be used as a diagnostic marker for muscle atrophy.

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Sequential changes in in vivo muscle and liver protein synthesis and plasma and tissue glutamine levels in sepsis in the rat

Clinical Science ◽

10.1042/cs1010295 ◽

2001 ◽

Vol 101 (3) ◽

pp. 295-304 ◽

Cited By ~ 10

Author(s):

Michael J. O'LEARY ◽

Colin N. FERGUSON ◽

Michael J. RENNIE ◽

Charles J. HINDS ◽

John H. COAKLEY ◽

...

Keyword(s):

Protein Synthesis ◽

Protein Content ◽

Total Protein ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Total Protein Content ◽

Sham Operation ◽

Liver Protein ◽

Male Wistar Rats

We have investigated sequential changes in skeletal muscle and hepatic protein synthesis following sepsis, and their relationship to changes in circulating and tissue glutamine concentrations. Male Wistar rats underwent caecal ligation and puncture (CLP) or sham operation, with starvation, and were killed 24, 72 or 96 h later. A group of non-operated animals were killed at the time of surgery. Protein synthesis was determined using a flooding dose of l-[4-3H] phenylalanine, and glutamine concentrations were measured by an enzymic fluorimetric assay. Protein synthesis in gastrocnemius muscle fell in all groups. Gastrocnemius total protein content was reduced after CLP and at 72 and 96 h after sham operation. After CLP, protein synthesis was lower at 24 h, and total protein content was lower at 72 and 96 h, than in sham-operated animals. CLP was associated with increased liver protein synthesis at all time points, whereas there was no change after sham operation. Liver protein content did not change after CLP, but was lower at 72 and 96 h after sham operation than in non-operated animals. Plasma glutamine concentrations were reduced at 24 h after sham operation, and at 72 and 96 h after CLP. Muscle glutamine concentrations were reduced in all groups, with the decrease being greater following CLP than after sham operation. In the liver, glutamine concentrations were unchanged after CLP, but increased after sham operation. In rats with sepsis, decreases in muscle protein synthesis and content are associated with markedly reduced muscle glutamine concentrations. Plasma glutamine concentrations are initially maintained, but fall later. In liver, protein synthesis is increased, while glutamine concentrations are preserved. These results support a peripheral-to-splanchnic glutamine flux in sepsis.

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