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11. Effect of intermittent feeding with high-fat diet on changes of glycogen, protein and fat content in liver and skeletal muscle in the laboratory mouse

Creator:
Křížová, E. and Šimek, V.
Type:
article, model:article, and TEXT
Subject:
intermittent feeding, high-fat diet, metabolism, liver, and skeletal muscle
Language:
English
Description:
After 8 weeks of intermittent fasting, mice fed both a standard laboratory diet and a high-fat diet became hyperphagic and showed an increased amount of glycogen storage in the liver. An important effect of the adaptation to intermittent feeding with a high-fat diet seems to be an activation of the oxidation of lipids. Lipid oxidation prevails over lipogenesis so that the protein levels in the liver and skeletal muscle are preserved and maintained constant.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

12. Effect of prior chronic aerobic exercise on overload-induced skeletal muscle hypertrophy in mice

Creator:
Siriguleng, Koike, T, Natsume, Y, Iwama, S, and Oshida, Y
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
svaly, muscles, aerobic exercise, skeletal muscle, hypertrophy, 14, and 612
Language:
English
Description:
This study aimed to examine how regular aerobic training can affect the muscle hypertrophy induced by overloading. Male C57BL/6J mice were randomly divided into three groups: rest group, low-intensity aerobic exercise group, and high-intensity aerobic exercise group. Mice in the exercise groups were assigned to run at a speed of 10 m/min (low-intensity) or 25 m/min (high-intensity) for 30 min/day, five days/week, for four weeks. Then, the right hind leg gastrocnemius muscles were surgically removed to overload the plantaris and soleus muscles, while the left hind leg was subjected to a sham-operation. Both the plantaris and soleus muscles grew larger in the overloaded legs than those in the sham-operated legs. Muscle growth increased in the plantaris muscles in the low-intensity exercise group compared to that in the rest or high-intensity exercise groups at one and two weeks after overloading. This enhancement was not observed in the soleus muscles. Consistently, we observed changes in the expression of proteins involved in anabolic intracellular signaling, including Akt, mechanistic target of rapamycin (mTOR), and p70S6K, in the plantaris muscles. Our data showed for the first time that chronic low-intensity aerobic exercise precipitates overload-induced muscle growth., Siriguleng, T. Koike, Y. Natsume, S. Iwama, Y. Oshida., and Obsahuje bibliografii
Rights:
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13. Effects of rapid or slow body weight reduction on intramuscular protein degradation pathways during equivalent weight loss on rats

Creator:
Nonaka, Y., Urashima, S., Inai, M., Nishimura, S., Higashida, K., and Terada, S.
Type:
article, model:article, and TEXT
Subject:
skeletal muscle, fasting, autophagy-lysosome, calorie restriction, and ubiquitin-proteasome
Language:
English
Description:
The purpose of this study was to compare the effects of shortterm fasting-induced rapid weight loss with those of slower but equivalent body weight loss induced by daily calorie restriction on muscle protein degradation pathways and muscle protein content. Male Fischer rats were subjected to either 30 % calorie restriction for 2 weeks to slowly decrease body weight (Slow) or 3-day fasting to rapidly decrease body weight by a comparable level of that of the Slow group (Rapid). The final body weights were about 15 % lower in both the Slow and Rapid groups than in the Con group (p<0.001). The total protein content and wet weight of fast-twitch plantaris muscle, but not slow-twitch soleus muscle, were significantly lower in the Rapid group compared with the control rats fed ad libitum. Substantial increases in the expression ratio of autophagosomal membrane proteins (LC3-II/-I ratio) and polyubiquitinated protein concentration, used as biomarkers of autophagy-lysosome and ubiquitinproteasome activities, respectively, were observed in the plantaris muscle of the Rapid group. Moreover, the LC3-II/-I ratio and polyubiquitinated protein concentration were negatively correlated with the total protein content and wet weight of plantaris muscle. These results suggest that short-term fastinginduced rapid body weight loss activates autophagy-lysosome and ubiquitin-proteasome systems more strongly than calorie restriction-induced slower weight reduction, resulting in muscular atrophy in fast-twitch muscle.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

14. Effects of voluntary running exercise on skeletal muscle properties in nonobese rats with type 2 diabetes

Creator:
Nakamoto, Isuzu and Ishihara, Akihiko
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
Goto-Kakizaki rat, oxidative capacity, Pgc-1α mRNA, skeletal muscle, type 2 diabetes, and voluntary running exercise
Language:
English
Description:
The skeletal muscles of animals and humans with type 2 diabetes have decreased oxidative capacity. Aerobic exercise can improve muscle oxidative capacity, but no data are available on the amount of exercise required. We investigated the effects of voluntary running exercise and running distance on the skeletal muscle properties of nonobese rats with type 2 diabetes. Six-week-old male diabetic Goto-Kakizaki rats were divided into nonexercised (GK) and exercised (GK-Ex) groups. The rats in the GK-Ex group were permitted voluntary running exercise on wheels for 6 weeks. Age-matched male Wistar rats (WR) were used as nondiabetic controls. Fasting blood glucose and HbA1c levels were higher in the GK and GK-Ex groups than in the WR group and lower in the GK-Ex group than in the GK group. Succinate dehydrogenase (SDH) activity and peroxisome proliferator-activated receptor γ coactivator-1α (Pgc-1α) mRNA levels in the soleus and plantaris muscles were higher in the WR and GK-Ex groups than in the GK group. HbA1c and total cholesterol levels were negatively correlated with running distance and SDH activity and Pgc-1α mRNA levels in the soleus muscle were positively correlated with running distance. The onset and progression of diabetes in nonobese diabetic rats were effectively inhibited by running longer distances.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

15. Excess of free fatty acids as a cause of metabolic dysfunction in skeletal muscle

Creator:
Jana Tůmová, Michal Anděl, and Jan Trnka
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, obezita, inzulinová rezistence, obesity, insulin resistance, free fatty acids, skeletal muscle, mitochondrial function, 14, and 612
Language:
English
Description:
Obesity is often associated with metabolic impairments in peripheral tissues. Evidence suggests an excess of free fatty acids (FFA) as one factor linking obesity and related pathological conditions and the impact of FFA overload on skeletal muscle metabolism is described herein. Obesity is associated with dysfunctional adipose tissue unable to buffer the flux of dietary lipids. Resulting increased levels and fluxes of plasma FFA lead to ectopic lipid deposition and lipotoxicity. FFA accumulated in skeletal muscle are associated with insulin resistance and overall cellular dysfunction. Mechanisms supposed to be involved in these conditions include the Randle cycle, intracellular accumulation of lipid metabolites, inflammation and mitochondrial dysfunction or mitochondrial stress. These mechanisms are described and discussed in the view of current experimental evidence with an emphasis on conflicting theories of decreased vs. increased mitochondrial fat oxidation associated with lipid overload. Since different types of FFA may induce diverse metabolic responses in skeletal muscle cells, this review also focuses on cellular mechanisms underlying the different action of saturated and unsaturated FFA., J. Tumova, M. Andel, J. Trnka., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

16. Expression of HIF-1α and VEGF in skeletal muscle of plateau animals in response to hypoxic stress

Creator:
Xie, H.-C., He, J.-P., Zhu, J.-F., and Li, J.-G.
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, svaly, stres (fyziologie), muscles, stress (physiology), HIF-1α, VEGF, skeletal muscle, hypoxic stress, 14, and 612
Language:
English
Description:
Hypoxia-inducible factor-1α (HIF-1α) transcriptionally regulates expression of several target genes in protecting tissues against hypoxia. With hypoxic stress, vascular endothelial growth factor (VEGF) is a signal protein produced by cells and further contributes to improvement of vascular functions and restoring the oxygen supply to tissues. In this current study, we first hypothesized that the protein levels of HIF-1α and VEGF are reduced in skeletal muscles of plateau animals [China Qinghai- Tibetan plateau pikas (ochotona curzoniae)] in response to hypoxia as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. We further hypothesized that HIF-1α plays a role in regulating expression of VEGF in skeletal muscle. Note that HIF-1α and VEGF were determined by using two-site immunoenzymatic assay (ELISA) methods. Our results demonstrated that hypoxic stress induced by exposure of lower O2 (6 h) significantly increased the levels of HIF-1α and VEGF in the oxidative and glycolytic muscles of SD rats and pikas (P<0.05 vs. normoxic conditions). Notably, the increases in HIF-1α and VEGF were significantly less in pikas (P<0.05, vs. SD controls) than in SD rats. In addition, a linear relationship was observed between amplified HIF-1α and VEGF in oxidative muscle (r=0.76 and P<0.01) and glycolytic muscle (r=0.72 and P<0.01) and inhibiting HIF-1α significantly decreased expression of VEGF induced by hypoxic stress in skeletal muscles (P<0.05). Overall, our findings suggest that (1) responsiveness of HIF-1α and VEGF in skeletal muscles to hypoxic stress is blunted in plateau animals, and (2) HIF-1α has a regulatory effect on VEGF under hypoxic environment., H.-C. Xie, J.-P. He, J.-F. Zhu, J.-G. Li., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

17. Glycation of myofibrillar proteins and ATPase activity after incubation with eleven sugars

Creator:
Syrový, I.
Type:
article, model:article, and TEXT
Subject:
glycation, myofibrils, ATPase activity, sugars, and skeletal muscle
Language:
English
Description:
Rat skeletal muscle myofibrils were incubated in the presence of D-glucose, D-fructose, D-galactose, D-ribose, D-tagatose, D-arabinose, D-xylose, D-mannose, L-sorbose, L-rhamnose or DL-glyceraldehyde and myofibrillar ATPase activity as well as the extent of glycation was measured. The attachment of sugars to proteins during glycation was generally dependent on the percentage of a given sugar present in the open-chain form. Glycation resulted in the decrease of myofibrillar ATPase activity. This decrease was low after incubation of myofibrillar proteins with slowly glycating sugars (e.g. glucose) and high with fast glycating sugars (e.g. ribose or glyceraldehyde). ATPase activity was less reduced in the presence of /3-mercaptoethanol.
Rights:
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18. Immunocytochemical demonstration of M1 muscarinic acetylcholine receptors at the presynaptic and postsynaptic membranes of rat diaphragm endplates: A. I. Malomouzh ... [et al.]

Creator:
Malomouzh, A. I., Arkhipova, S. S., Nikolsky, E. E., and František Vyskočil
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, mammalian neuromuscular junction, skeletal muscle, M1 muscarinic receptor, 14, and 612
Language:
English
Description:
M1-muscarinic acetylcholine (ACh) receptors (M1R) were directly demonstrated immunocytochemic ally in electronmicroscopic images of rat diaphragm neuromus cular junctions (NMJ). Specific electron-dense granules were located at presynaptic nerve ending membranes and in the sa rcolemma in the depths of postsynaptic folds. This first visualization of M1R on both sides of the NMJ is in agreement with previous pharmacological data on the regulatory role of M1R in quantal and non-quantal ACh release. and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

19. Increased circulating and epicardial adipose tissue mRNA expression of fibroblast growth factor-21 after cardiac surgery: possible role in postoperative inflammatory response and insulin resistance

Creator:
Tomáš Kotulák, Drápalová, J., Petr Kopecký, Zdeňka Lacinová, Kramář, P., Hynek Říha, Ivan Netuka, Malý, J., Daniel Housa, Jan Bláha, Štěpán Svačina, and Martin Haluzík
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, kardiochirurgie, inzulinová rezistence, cardiac surgery, insulin resistance, fibroblast growth factor-21, adipose tissue, skeletal muscle, 14, and 612
Language:
English
Description:
We studied the changes in seru m fibroblast growth factor-21 (FGF-21) concentrations, its mR NA, and protein expression in skeletal muscle and adipose tissue of 15 patients undergoing cardiac surgery. Blood samples were obtained: prior to initiation of anesthesia, prior to the start of extracorporeal circulation, upon completion of the surger y, and 6, 24, 48, and 96 hours after the end of the surgery. Tissue sampling was performed at the start and end of surgery. The mean baseline serum FGF-21 concentration was 63.1 (43.03-113. 95) pg/ml and it increased during surgery with peak 6 ho urs after its end [385.5 (274.55-761.65) pg/ml, p<0.001], and return ed to baseline value [41.4 (29.15-142.83) pg/ml] 96 hours afte r the end of the surgery. Serum glucose, insulin, CRP, IL-6, IL-8, MCP-1, and TNF-alpha concentrations significantly increased during the surgery. Baseline FGF-21 mRNA expression in skeletal muscle was higher than in both adipose tissue depots and it was not affected by the surgery. Epicardial fat FGF-21 mRNA increased after surgery. Muscle FGF-21 mRNA positively correlated with blood glucose levels at the end of the surgery. Our data suggest a possible role of FGF-21 in the regulation of glucose metabolism and insulin sensitivity in surgery-related stress., T. Kotulák ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

20. Levels of energy-related metabolites in intact and isolated perfused-superfused rat skeletal muscles

Creator:
Štefl, B., Mejsnar, J. A., and Karasová, J.
Type:
article, model:article, and TEXT
Subject:
skeletal muscle, metabolites, energetics, and flow-dependent respiration
Language:
English
Description:
Adenosine 5'-triphosphate (ATP), phosphocreatine (PCr), creatine (Cr), inorganic phosphate (Pi), lactate (LAC), pyruvate (PYR) and glycogen as glucose (GLG) were determined and free adenosine 5'-diphosphate (ADP) was calculated from ATP:creatine phosphokinase (CPK) reaction in the gracilis muscle of cold-acclimated rats in vivo, and in completely isolated muscles under medium perfusion and superfusion in vitro, using the freezeclamping method. The mean in vivo levels (wmol/g w.w.) were: ATP 4.8, PCr 12.0, Cr 7.8, Pi 1.6, LAC 1.6, PYR 0.09, GLG 22.9, ADP 0.62 x 10-3. Isolation of the muscle (about 11 min of anoxia followed by perfusion in the air with a high pC>2 medium) decreased macroergic phosphate levels (ATP 3.0 , PCr 8.3). In isolated muscles perfused with a high pC>2 medium (99 kPa O2, perfusion rate 70 /rl/min) and simultaneously superfused with a low p02 medium (6.2 kPa O2, 2.3 ml/min) at 28 °C in vitro the levels of metabolites were (wmol/g w.w.): ATP 3.1, PCr 8.5, Cr 5.6, Pi 0.9, LAC 2.1, PYR 0.19, GLG 6.6, ADP 0.44 x 10-3. The mean steady oxygen uptake of the isolated muscle was 97 nmol O2 x min-1 x g-1 w.w. Thus, the levels of macroergic phosphates and their derivatives are lower after isolation and perfusion of the muscle, but the creatine charge [PCr]/([PCr]-f[Cr]] remains stable (0.61 in vivo versus 0.60 in the isolated muscle). This indicates that the steady-state and high energy status of the isolated perfused-superfused gracilis muscle is maintained.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public