Exposure to pressure stimulus enhances succinate dehydrogenase activity in L6 myoblasts

2004 ◽  
Vol 287 (6) ◽  
pp. E1064-E1069 ◽  
Author(s):  
Noriteru Morita ◽  
Kenji Iizuka ◽  
Koichi Okita ◽  
Takashi Oikawa ◽  
Kazuya Yonezawa ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Succinate Dehydrogenase ◽  
Skeletal Muscles ◽  
Colorimetric Assay ◽  
Nerve Impulse ◽  
Metabolic Responses ◽  
L6 Cells ◽  
Pressure Stimulus ◽  
Original Apparatus

Contraction of skeletal muscle generates pressure stimuli to intramuscular tissues. However, the effects of pressure stimuli, other than those created by electricity or nerve impulse, on physiological and biochemical responses in skeletal muscles are unknown. The purpose of this study is to examine the effects of a pure pressure stimulus on metabolic responses in a skeletal muscle cell line. Atmospheric pressure was applied to L6 myoblasts using an original apparatus. Succinate dehydrogenase (SDH) activity was evaluated by colorimetric assay using tetrazolium monosodium salt. The amounts of 2-deoxy-[3H]glucose uptake and lactate release were measured. SDH activity was 2.6- to 2.9-fold higher in pressurized L6 cells than in nonpressurized L6 cells ( P < 0.01), and 2-deoxy-[3H]glucose uptake was 2.2-fold higher ( P < 0.001). In addition, the amount of released lactate decreased from 6.8 to 3.7 μmol/dish when pressure was applied ( P < 0.001). In contrast, the intracellular lactate contents of the pressurized cells were higher than those of nonpressurized cells ( P < 0.01). However, the total amount of released lactate and intracellular lactate was lower in the pressurized cells than in nonpressurized cells. These findings demonstrate that a pure pressure stimulus enhances aerobic metabolism in L6 skeletal muscle cells and raise the possibility that elevated intramuscular pressure during muscle activity may be an important factor in stimulating oxidative metabolic responses in skeletal muscles.

BRSK1 regulates glucose uptake in L6 cells and mouse skeletal muscle

2013 ◽  
Vol 7 ◽  
pp. e84-e85
Author(s):  
Xu Yan ◽  
Kazuhiro Nakano ◽  
Ding An ◽  
Michael F. Hirshman ◽  
Laurie J. Goodyear
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Mouse Skeletal Muscle ◽  
L6 Cells

Prolonged suppression of glucose metabolism causes insulin resistance in rat skeletal muscle

1997 ◽  
Vol 272 (2) ◽  
pp. E288-E296 ◽  
Author(s):  
J. K. Kim ◽  
J. H. Youn
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Skeletal Muscles ◽  
Glycogen Synthesis ◽  
Whole Body ◽  
Metabolic Fluxes ◽  
Phosphate Inhibition ◽  
Intracellular Glucose

To determine whether an impairment of intracellular glucose metabolism causes insulin resistance, we examined the effects of suppression of glycolysis or glycogen synthesis on whole body and skeletal muscle insulin-stimulated glucose uptake during 450-min hyperinsulinemic euglycemic clamps in conscious rats. After the initial 150 min to attain steady-state insulin action, animals received an additional infusion of saline, Intralipid and heparin (to suppress glycolysis), or amylin (to suppress glycogen synthesis) for up to 300 min. Insulin-stimulated whole body glucose fluxes were constant with saline infusion (n = 7). In contrast, Intralipid infusion (n = 7) suppressed glycolysis by approximately 32%, and amylin infusion (n = 7) suppressed glycogen synthesis by approximately 45% within 30 min after the start of the infusions (P < 0.05). The suppression of metabolic fluxes increased muscle glucose 6-phosphate levels (P < 0.05), but this did not immediately affect insulin-stimulated glucose uptake due to compensatory increases in other metabolic fluxes. Insulin-stimulated whole body glucose uptake started to decrease at approximately 60 min and was significantly decreased by approximately 30% at the end of clamps (P < 0.05). Similar patterns of changes in insulin-stimulated glucose fluxes were observed in individual skeletal muscles. Thus the suppression of intracellular glucose metabolism caused decreases in insulin-stimulated glucose uptake through a cellular adaptive mechanism in response to a prolonged elevation of glucose 6-phosphate rather than the classic mechanism involving glucose 6-phosphate inhibition of hexokinase.

Adiponectin concentration is associated with muscle insulin sensitivity, AMPK phosphorylation, and ceramide content in skeletal muscles of men but not women

2013 ◽  
Vol 114 (5) ◽  
pp. 592-601 ◽  
Author(s):  
Louise D. Høeg ◽  
Kim A. Sjøberg ◽  
Anne-Marie Lundsgaard ◽  
Andreas B. Jordy ◽  
Natalie Hiscock ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
Skeletal Muscles ◽  
Serum Adiponectin ◽  
Negatively Associated ◽  
Ampk Phosphorylation ◽  
Ceramide Content ◽  
Sensitizing Effect

Adiponectin is an adipokine that regulates metabolism and increases insulin sensitivity. Mechanisms behind this insulin-sensitizing effect have been investigated in rodents, but little is known in humans, especially in skeletal muscle. Women have higher serum concentrations of adiponectin than men and are generally more insulin sensitive in skeletal muscle than men. We show here that large differences exist between men and women with regard to apparent adiponectin regulation of insulin-stimulated glucose uptake in skeletal muscle. Serum adiponectin was significantly associated with leg glucose uptake in healthy, young, lean men, but the association was absent in women. In addition, serum adiponectin was significantly associated with AMP-activated protein kinase (AMPK) phosphorylation in skeletal muscles of men but not in women. Serum adiponectin was also significantly, negatively associated with skeletal muscle ceramide content in men only, and interestingly, ceramide content was negatively associated with adiponectin receptor 1 (AdipoR1) expression in skeletal muscles of men. Women had lower AdipoR1 expression in skeletal muscle and a lower percentage of glycolytic adiponectin-sensitive type 2 muscle fibers than men. These associations suggest that the insulin-sensitizing effect of adiponectin on human male skeletal muscles may be mediated via AdipoR1 to activation of AMPK, leading to lowering of ceramide content. The lower skeletal muscle AdipoR1 protein expression and lower expression of adiponectin-sensitive type 2 muscle fibers in women than in men may explain the apparent lesser sensitivity to adiponectin in women.

scholarly journals Glucose-transporter (GLUT4) protein content in oxidative and glycolytic skeletal muscles from calf and goat

1995 ◽  
Vol 305 (2) ◽  
pp. 465-470 ◽  
Author(s):  
J F Hocquette ◽  
F Bornes ◽  
M Balage ◽  
P Ferre ◽  
J Grizard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Skeletal Muscles ◽  
Glucose Transporter ◽  
Transporter Protein ◽  
Rat Muscle ◽  
Glucose Transporter Glut4

It is well accepted that skeletal muscle is a major glucose-utilizing tissue and that insulin is able to stimulate in vivo glucose utilization in ruminants as in monogastrics. In order to determine precisely how glucose uptake is controlled in various ruminant muscles, particularly by insulin, this study was designed to investigate in vitro glucose transport and insulin-regulatable glucose-transporter protein (GLUT4) in muscle from calf and goat. Our data demonstrate that glucose transport is the rate-limiting step for glucose uptake in bovine fibre strips, as in rat muscle. Insulin increases the rate of in vitro glucose transport in bovine muscle, but to a lower extent than in rat muscle. A GLUT4-like protein was detected by immunoblot assay in all insulin-responsive tissues from calf and goat (heart, skeletal muscle, adipose tissue) but not in liver, brain, erythrocytes and intestine. Unlike the rat, bovine and goat GLUT4 content is higher in glycolytic and oxido-glycolytic muscles than in oxidative muscles. In conclusion, using both a functional test (insulin stimulation of glucose transport) and an immunological approach, this study demonstrates that ruminant muscles express GLUT4 protein. Our data also suggest that, in ruminants, glucose is the main energy-yielding substrate for glycolytic but not for oxidative muscles, and that insulin responsiveness may be lower in oxidative than in other skeletal muscles.

The TRPV1 channel regulates glucose metabolism

2019 ◽  
Vol 317 (4) ◽  
pp. E667-E676 ◽  
Author(s):  
Amanda J. Page ◽  
George Hatzinikolas ◽  
Andrew D. Vincent ◽  
Paul Cavuoto ◽  
Gary A. Wittert
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Transient Receptor Potential ◽  
Uncoupling Protein ◽  
Acid Amide ◽  
Pyruvate Dehydrogenase Kinase ◽  
L6 Cells ◽  
Trpv1 Channels

Endocannabinoids (ECs) mediate effects via cannabinoid receptor types 1 and 2 (CB1 and 2) and transient receptor potential channel-vanilloid subfamily member 1 (TRPV1) channels. In high-fat diet (HFD)-induced obese mice overactivity of the EC system and inhibition of CB1 increase skeletal muscle glucose uptake. We explored the role of TRPV1. Male TRPV1+/+(WT) and TRPV1−/−(KO)-mice were fed (20 wk) a standard laboratory diet (SLD) or HFD. An intraperitoneal glucose tolerance test was performed. RT-PCR was performed to measure mRNA of genes involved in glucose/lipid metabolism and the EC system in soleus (SOL) and extensor digitorum longus (EDL) muscles. Cultured L6 cells were used to measure glucose uptake in skeletal muscle. HFD mice weighed more and had higher insulin levels than SLD mice, with no genotype differences. Basal and peak glucose were higher in HFD mice irrespective of genotype, but glucose cleared faster in HFD WT vs. HFD KO-mice. 2-Arachidonoylglycerol augmented insulin-induced glucose uptake in skeletal L6-cells, an effect blocked by the TRPV1 antagonist SB-366791. In EDL, fatty acid amide hydrolase (FAAH) mRNA was increased in KO vs. WT mice, irrespective of diet. Pyruvate dehydrogenase kinase isozyme 4 (PDK4) and mitochondrial uncoupling protein 3 (UCP3) were elevated and FA desaturase 2 (FADS2) mRNA lower in HFD mice, irrespective of genotype. CB1 and stearoyl-CoA desaturase 1 (SCD1) were lower in HFD WT mice only. In SOL, PDK4, UCP3, hormone-sensitive lipase (LIPE), fatty acid translocase (CD36), and carnitine palmitoyl transferase 2 (CPT2) were elevated and SCD1, FAAH, FADS2, and Troponin 1 (TNNC1) mRNA lower in HFD mice, irrespective of genotype. In conclusion, TRPV1 regulates glucose disposal in HFD mice. We propose that TRPV1 plays a role in coordinating glucose metabolism in EDL under conditions of metabolic stress.

scholarly journals Selectivity of the insulin-like actions of vanadate on glucose and protein metabolism in skeletal muscle

1985 ◽  
Vol 232 (1) ◽  
pp. 273-276 ◽  
Author(s):  
A S Clark ◽  
J M Fagan ◽  
W E Mitch
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Insulin Receptor ◽  
Glucose Uptake ◽  
Protein Metabolism ◽  
Glucose Oxidation ◽  
Glycogen Synthesis ◽  
Metabolic Responses ◽  
Receptor Phosphorylation ◽  
Stimulation Of

To determine if vanadate has insulin-like actions in skeletal muscle, we measured its effects on glucose and protein metabolism in epitrochlearis muscles of rats. Compared with insulin, vanadate increased glucose uptake, glycogen synthesis and glycolysis to a lesser degree, but caused a greater stimulation of lactate and glucose oxidation. Unlike insulin, vanadate did not change either protein synthesis or degradation. These different metabolic responses could be related to the different pattern of insulin-receptor phosphorylation caused by insulin and vanadate.

scholarly journals Rab GAPs AS160 and Tbc1d1 play nonredundant roles in the regulation of glucose and energy homeostasis in mice

2016 ◽  
Vol 310 (4) ◽  
pp. E276-E288 ◽  
Author(s):  
Stefan R. Hargett ◽  
Natalie N. Walker ◽  
Susanna R. Keller
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Glucose Homeostasis ◽  
Skeletal Muscles ◽  
Energy Homeostasis ◽  
Glucose Transporter ◽  
Fiber Type ◽  
Rab Gtpase ◽  
Glut4 Expression ◽  
Deficient Mice

The related Rab GTPase-activating proteins (Rab GAPs) AS160 and Tbc1d1 regulate the trafficking of the glucose transporter GLUT4 that controls glucose uptake in muscle and fat cells and glucose homeostasis. AS160- and Tbc1d1-deficient mice exhibit different adipocyte- and skeletal muscle-specific defects in glucose uptake, GLUT4 expression and trafficking, and glucose homeostasis. A recent study analyzed male mice with simultaneous deletion of AS160 and Tbc1d1 (AS160−/−/Tbc1d1−/− mice). Herein, we describe abnormalities in male and female AS160−/−/Tbc1d1−/− mice on another strain background. We confirm the earlier observation that GLUT4 expression and glucose uptake defects of single-knockout mice join in AS160−/−/Tbc1d1−/− mice to affect all skeletal muscle and adipose tissues. In large mixed fiber-type skeletal muscles, changes in relative basal GLUT4 plasma membrane association in AS160−/− and Tbc1d1−/− mice also combine in AS160−/−/Tbc1d1−/− mice. However, we found different glucose uptake abnormalities in isolated skeletal muscles and adipocytes than reported previously, resulting in different interpretations of how AS160 and Tbc1d1 regulate GLUT4 translocation to the cell surface. In support of a larger role for AS160 in glucose homeostasis, in contrast with the previous study, we find similarly impaired glucose and insulin tolerance in AS160−/−/Tbc1d1−/− and AS160−/− mice. However, in vivo glucose uptake abnormalities in AS160−/−/Tbc1d1−/− skeletal muscles differ from those observed previously in AS160−/− mice, indicating additional defects due to Tbc1d1 deletion. Similar to AS160- and Tbc1d1-deficient mice, AS160−/−/Tbc1d1−/− mice show sex-specific abnormalities in glucose and energy homeostasis. In conclusion, our study supports nonredundant functions for AS160 and Tbc1d1.

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