scholarly journals Glutamine metabolism in skeletal muscles from the broiler chick (Gallus domesticus) and the laboratory rat (Rattus norvegicus)

1991 ◽  
Vol 274 (3) ◽  
pp. 769-774 ◽  
Author(s):  
G Wu ◽  
J R Thompson ◽  
V E Baracos
Keyword(s):  
Skeletal Muscle ◽  
Rattus Norvegicus ◽  
Skeletal Muscles ◽  
Species Difference ◽  
Plasma Concentrations ◽  
Subcellular Location ◽  
Glutamine Metabolism ◽  
Oxidative Decarboxylation ◽  
Rat Skeletal Muscle ◽  
Glutaminase Activity

Oxidative decarboxylation of L-[1-14C]glutamine was studied in isolated chick and rat skeletal muscles incubated in the presence of glucose, insulin and plasma concentrations of amino acids. (1) The rate of oxidative decarboxylation of L-[1-14C]glutamine was high, and exceeded that of L-[1-14C]leucine in all muscles. (2) The rate of oxidative decarboxylation of L-[1-14C]glutamine increased with increasing intracellular concentrations of glutamine. (3) The activities of glutamine aminotransferases K and L were more than 10-fold greater in rat than in chick skeletal muscles. (4) Mitochondrial phosphate-activated glutaminase activity was approx. 10-fold greater in chick than in rat skeletal muscles and increased with increasing glutamine concentrations. (5) An inhibitor of glutaminase, 6-diazo-5-oxo-L-norleucine, inhibited the rate of glutamine decarboxylation in chick, but not in rat, skeletal muscle. These findings suggest that glutamine degradation in skeletal muscle may be substantial and may make an important contribution to the regulation of intramuscular glutamine concentrations. A species difference in the pathways and the subcellular location for the conversion of glutamine into 2-oxoglutarate in rat and chick skeletal muscles is implied by the relative activities of glutamine-degrading enzymes.

Glutamine Metabolism in Skeletal Muscle of Glucocorticoid-Treated Rats

1990 ◽  
Vol 79 (2) ◽  
pp. 139-147 ◽  
Author(s):  
M. Salleh M. Ardawi ◽  
Yasir S. Jamal
Keyword(s):  
Skeletal Muscle ◽  
Exchange Rates ◽  
Skeletal Muscles ◽  
Plasma Concentrations ◽  
Maximal Activity ◽  
Glutamine Metabolism ◽  
Dexamethasone Treatment ◽  
Concentration Difference

1. The effect of dexamethasone (30 μg day−-1 100 g−-1 body weight) on the regulation of glutamine metabolism was studied in skeletal muscles of rats after 9 days of treatment. 2. Dexamethasone resulted in negative nitrogen balance, and produced increases in the plasma concentrations of alanine (23.4%) and insulin (158%) but a decrease in the plasma concentration of glutamine (28.7%). 3. Dexamethasone treatment increased the rate of glutamine production in muscle, skin and adipose tissue preparations, with muscle production accounting for over 90% of total glutamine produced by the hindlimb. 4. Blood flow and arteriovenous concentration difference measurements across the hindlimb showed an increase in the net exchange rates of glutamine (25.3%) and alanine (90.5%) in dexamethasone-treated rats compared with corresponding controls. 5. Dexamethasone treatment produced significant decreases in the concentrations of skeletal muscle glutamine (51.8%) and 2-oxoglutarate (50.8%). The concentrations of alanine (16.2%), pyruvate (45.9%), ammonia (43.3%) and inosine 5′-phosphate (141.8%) were increased. 6. The maximal activity of glutamine synthetase was increased (21–34%), but there was no change in that of glutaminase, in muscles of dexamethasone-treated rats. 7. It is concluded that glucocorticoid administration enhances the rates of release of both glutamine and alanine from skeletal muscle of rats (both in vitro and in vivo). This may be due to changes in efflux and/or increased intracellular formation of glutamine and alanine.

scholarly journals Alkaline phosphatase and dipeptidylpeptidase IV staining of tissue components of skeletal muscle: a comparative study.

1990 ◽  
Vol 38 (12) ◽  
pp. 1907-1912 ◽  
Author(s):  
M Grim ◽  
B M Carlson
Keyword(s):  
Skeletal Muscle ◽  
Alkaline Phosphatase ◽  
Skeletal Muscles ◽  
Laboratory Animals ◽  
Staining Reaction ◽  
Rat Skeletal Muscle ◽  
Dipeptidylpeptidase Iv ◽  
Dpp Iv ◽  
Intramuscular Nerves ◽  
Interspecies Variability

A combined alkaline phosphatase (AP) and dipeptidlypeptidase IV (DPP IV) staining reaction has demonstrated enzymatic heterogeneity of the arterial and venous segments of capillaries in rat skeletal muscle. This study compared the staining reactions of skeletal muscles in many commonly used laboratory animals, including the axolotl, chick, quail, Monodelphys, rat, mouse, hamster, guinea pig, rabbit, dog, monkey, and human. DPP IV activity was found in the venous ends of the capillaries and in the endothelium of some larger veins in many of the species but was never demonstrated in the arterial side of the circulation. AP was found in the arterial ends of capillaries in all species except the axolotl, and it was also found in the endothelium of larger arteries of most species. AP activity was absent in venous endothelium of all species except for birds and Monodelphys. DPP IV activity was found in the perineurium of intramuscular nerves of most species, and AP activity was commonly seen in tendons and intramuscular connective tissue. The interspecies variability found in this study shows that care must be taken in comparing experimental data involving this technique from one species to another, but within a species the technique allows a fine level of discrimination between functionally distinct compounds of skeletal muscle tissue.

scholarly journals Increase in Subcellular GSK-3 Clusters in Insulin- and Adrenaline-treated Differentiated Rat Skeletal Muscle Fibres

2020 ◽  
Author(s):  
Katja Fink ◽  
Mateja Lobe Prebil ◽  
Nina Vardjan ◽  
Jorgen Jensen ◽  
Robert Zorec ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscles ◽  
Metabolic Regulation ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase 3 ◽  
Muscle Fibres ◽  
Optical Section ◽  
Rat Skeletal Muscle ◽  
Average Size ◽  
Skeletal Muscle Fibres

Glycogen synthase kinase 3 (GSK-3) plays an important role in metabolic regulation in skeletal muscles, and both insulin and adrenaline stimulate   GKS-3 phosphorylation. The aim of the present study was to study the effect of insulin and adrenaline on GSK-3 localisation in skeletal muscles.We characterized subcellular localization of (GSK-3) signal protein in fully differentiated muscle fibre by immunofluorescence and confocal microscopy. We stimulated muscle fibres with insulin and/or adrenaline. Images were analysed by segmentation of single central optical section of the muscle.We found GSK-3 to be localised in clusters. The number of GSK-3 clusters and their average size were increased after stimulation with insulin and/or adrenaline. Average GSK-3 particle size is linearly related to their quantity.We conclude that subcellular GSK-3 in isolated skeletal muscle fibres is localized in clusters and clustering increased after stimulation with insulin and/or adrenaline.

Molecular characterization of rat skeletal muscle myosin light chain kinase

1989 ◽  
Vol 256 (2) ◽  
pp. C399-C404 ◽  
Author(s):  
B. P. Herring ◽  
M. H. Nunnally ◽  
P. J. Gallagher ◽  
J. T. Stull
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Skeletal Muscles ◽  
Myosin Light Chain ◽  
Cardiac Tissue ◽  
Rat Skeletal Muscle ◽  
Skeletal Muscle Myosin ◽  
Slow Twitch ◽  
Muscle Myosin

A 1.85-kilobase (kb) cDNA has been isolated that encodes the catalytic and calmodulin binding domains of rat skeletal muscle myosin light chain kinase. The cDNA hybridized to a 3.3-kb RNA present in fast- and slow-twitch skeletal muscles. The reported enzymatic activity (3-fold greater in fast- than slow-twitch skeletal muscles) reflects the relative abundance of this RNA in the two types of skeletal muscle. No hybridization of the cDNA was detected to RNA isolated from smooth or nonmuscle tissues. The clone cross hybridized to a 2.2-kb RNA present in cardiac tissue. Ribonuclease protection analysis of skeletal and cardiac muscle RNA revealed major differences in the two hybridizing RNAs. Thus rat skeletal muscle contains a single myosin light chain kinase isoform, which is distinct from the cardiac, smooth, and nonmuscle forms.

scholarly journals Isolation of Relaxing Particles from Rat Skeletal Muscles in Zonal Centrifuges

1965 ◽  
Vol 48 (5) ◽  
pp. 737-752 ◽  
Author(s):  
H. Schuel ◽  
L. Lorand ◽  
R. Schuel ◽  
N. G. Anderson
Keyword(s):  
Skeletal Muscle ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Skeletal Muscles ◽  
Microsomal Fraction ◽  
Differential Centrifugation ◽  
Rat Skeletal Muscle ◽  
Cytochrome Oxidase Activity ◽  
Soluble Phase ◽  
Enzymatic Marker

Supernatants of rat skeletal muscle homogenates were fractionated by differential centrifugation and by zonal centrifugation in sucrose density gradients. Cytochrome oxidase was employed as an enzymatic marker for locating mitochondria. The subcellular fractions were also assayed for their ability to prevent the ATP-induced contraction of myofibrils. Both the mitochondrial and microsomal fractions obtained by differential fractionation were found to be rich in such relaxing activity, and the microsomal fraction was appreciably contaminated by mitochondria. In contrast to this, when fractionation was carried out by means of zonal centrifugation (4200 RPM x 205 min. to 40,000 RPM x 60 min.), relaxing activity was found to be associated only with particles having the sedimentation characteristics of microsomes (s20,w estimated to be between 370 and 1880S). Relaxing activity was not detected in the regions of the gradient containing either the starting sample zone (soluble phase) or the mitochondrial peak. The microsomal relaxing particles showed negligible cytochrome oxidase activity.

Glutamine metabolism in rat skeletal muscle wounded with lambda-carrageenan

1987 ◽  
Vol 252 (1) ◽  
pp. E49-E56
Author(s):  
J. E. Albina ◽  
W. Henry ◽  
P. A. King ◽  
J. Shearer ◽  
B. Mastrofrancesco ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Inflammatory Infiltrate ◽  
Marked Decrease ◽  
Glutamine Metabolism ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Rat Skeletal Muscle ◽  
Glutamine Synthesis ◽  
Cellular Components

Wounding with lambda-carrageenan results in a marked decrease in the intracellular-free glutamine content of rat skeletal muscle. The potential mechanisms for this finding, including alterations in glutamine release, glutamine utilization, and glutamine synthesis, were investigated in rats under pentobarbital anesthesia. Wounding did not increase glutamine release from muscle during incubation or isolated hindlimb perfusion. Wounded muscle utilized more glutamine than nonwounded muscle, as measured both by the production of [14C]O2 and of -glutamate from labeled glutamine. Maximal glutamine synthetase activity was increased by wounding. The increase in glutamine synthetase activity in wounded muscle was prevented by adrenalectomy and restored by replacement doses of corticosterone in wounded adrenalectomized animals. The decrease in muscle free glutamine induced by wounding is therefore not mediated by an increase in the release of this amino acid, nor by a reduction in the tissue capacity for glutamine synthesis, but by an increase in glutamine utilization at the site of injury. This difference is apparently determined by the utilization of glutamine by the cellular components of the inflammatory infiltrate, which were shown to be capable of active glutaminolysis.

scholarly journals Akt Substrate of 160 kDa Dephosphorylation Rate Is Reduced in Insulin-Stimulated Rat Skeletal Muscle After Acute Exercise

2018 ◽  
pp. 143-147 ◽  
Author(s):  
E. B. ARIAS ◽  
H. WANG ◽  
G. D. CARTEE
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscles ◽  
Acute Exercise ◽  
Significant Trend ◽  
Rat Skeletal Muscle ◽  
Post Exercise ◽  
Akt Activation ◽  
Prior Exercise

Because greater Akt substrate of 160 kDa (AS160) phosphorylation has been reported in insulin-stimulated skeletal muscles without improved Akt activation several hours post-exercise, we hypothesized that prior exercise would result in attenuated AS160 dephosphorylation in insulin-stimulated rat skeletal muscle. Epitrochlearis muscles were isolated from rats that were sedentary (SED) or exercised 3 h earlier (3 h post-exercise; 3hPEX). Paired muscles were incubated with [3H]-2-deoxyglucose (2-DG) without insulin or with insulin. Lysates from other insulin-stimulated muscles from SED or 3hPEX rats were evaluated using AS160Thr642 and AS160Ser588 dephosphorylation assays. Prior exercise led to greater 2-DG uptake concomitant with greater AS160Thr642 phosphorylation and a non-significant trend (P=0.087) for greater AS160Ser588. Prior exercise also reduced AS160Thr642 and AS160Ser588 dephosphorylation rates. These results support the idea that attenuated AS160 dephosphorylation may favor greater AS160 phosphorylation post-exercise.

scholarly journals 4-Methyl-2-oxopentanoate oxidation by rat skeletal-muscle mitochondria

1979 ◽  
Vol 182 (2) ◽  
pp. 353-360 ◽  
Author(s):  
V W M Van Hinsbergh ◽  
J H Veerkamp ◽  
J F C Glatz
Keyword(s):  
Skeletal Muscle ◽  
Intermediate Formation ◽  
Inhibitory Effect ◽  
Oxidative Decarboxylation ◽  
Rat Skeletal Muscle ◽  
Mitochondrial Inner Membrane ◽  
Skeletal Muscle Mitochondria ◽  
Intact Muscle ◽  
Km Value ◽  
Branched Chain

1. Oxidative decarboxylation of 4-methyl-2-oxopentanoate (2-oxoisocaproate) by mitochondria of rat skeletal muscle showed biphasic kinetics. Two apparent Km values of 9.1 micronM and 0.78 mM were established. In broken mitochondria the rate of oxidation was lower and only the higher apparent Km value was found. 2. Isovalerylcarnitine inhibited 4-methyl-2-oxopentanoate oxidation in the presence and absence of carnitine, but isovaleryl-CoA had no inhibitory effect. 3. Addition of ADP enhanced 4-methyl-2-oxopentanolate oxidation. Malate, succinate and 2-oxoglutarate additionally increased the rate of oxidation, but in the absence of ADP succinate and 2-oxoglutarate inhibited. 4. Addition of rotenone and simultaneous addition of carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone (FCCP) and valinomycin markedly decreased 4-methyl-2-oxopentanoate oxidation. 5. These observations indicate that the branched-chain 2-oxo acid dehydrogenase complex is situated on the inner side of the mitochondrial inner membrane. 6. In mitochondria and homogenates CO2 was only produced by oxidative decarbosylation of 4-methyl-2-oxopentanoate. In intact muscle oxidation of this oxo acid proceeds more to completeness. 7. The physiological significance of intermediate formation during oxidation of branched-chain amino acids is discussed.

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