Evidence for inhibition of glucose transport in peripheral adrenergic neurons by cytochalasin B

1974 ◽  
Vol 26 (7) ◽  
pp. 545-546 ◽  
Author(s):  
D. M. Paton
Keyword(s):  
Glucose Transport ◽  
Cytochalasin B ◽  
Adrenergic Neurons

Glucose transport in isolated rat adipocytes with measurements of L-arabinose uptake.

1978 ◽  
Vol 234 (2) ◽  
pp. E112 ◽  
Author(s):  
J E Foley ◽  
S W Cushman ◽  
L B Salans
Keyword(s):  
Glucose Transport ◽  
Transport System ◽  
Cytochalasin B ◽  
Competitive Inhibition ◽  
Facilitated Transport ◽  
Time Dependent ◽  
Rat Adipocytes ◽  
A Value ◽  
System Data ◽  
Isolated Rat

Data is presented suggesting that rates of L-arabinose transport, calculated from L-[1-14C]arabinose uptake measurements, can be used as indicators of changes in the rates of glucose transport in isolated rat adipocytes. L-[1-14C]arabinose, at 37 degrees C, was found to be nonmetabolizable and taken up by adipocytes exponentially with time reaching 95% of equilibrium in 30 min. When L-arabinose is corrected for background, the corrected uptake values conform to the time-dependent monoexponential uptake relationshiop predicted for a facilitated transport system and are not significantly different from 0 in the presence of 70 micron cytochalasin B. Transport rates were calculated from corrected uptake values near the half-maximal uptake of L-arabinose and from a value of the total amount of L-arabinose in the cell at equilibrium. Competitive inhibition of L-arabinose transport by glucose and countertransport of L-arabinose in the presence of glucose suggest that L-arabinose and glucose share the same transport system. Data is presented demonstrating the effect of insulin and dexamethasone on the transport system that confirms the conclusions obtained by other investigators using other methods.

Kinetics of glucose transport in rat skeletal muscle membrane vesicles: effects of insulin and contractions

1992 ◽  
Vol 262 (5) ◽  
pp. E700-E711 ◽  
Author(s):  
T. Ploug ◽  
H. Galbo ◽  
T. Ohkuwa ◽  
J. Tranum-Jensen ◽  
J. Vinten
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Glucose Transport ◽  
Cytochalasin B ◽  
Equilibrium Distribution ◽  
Initial Rate ◽  
Membrane Vesicles ◽  
Membrane Preparation ◽  
Muscle Membrane ◽  
Distribution Space

To study the mechanism of acceleration of glucose transport in skeletal muscle after stimulation with insulin and contractions, we isolated a subcellular vesicular membrane fraction, highly enriched in the plasma membrane enzyme K(+)-stimulated p-nitrophenylphosphatase and also enriched in some intracellular membranes. Protein recovery, morphology, lipid content, marker enzyme activities, total intravesicular volume, Western blot quantitation of GLUT-1, and glucose-inhibitable cytochalasin B binding were identical in membrane fractions from control, insulin-stimulated, contraction-stimulated, and insulin- and contraction-stimulated muscle. Time course of D-[3H]glucose entry in membrane vesicles at equilibrium exchange conditions showed that initial rate of transport at 30 mM of glucose was increased 19-fold and that equilibrium distribution space was increased 4-fold in vesicles from maximum stimulated muscle. The effects of insulin and contractions on initial rate of transport as well as on equilibrium distribution space were additive, and stimulation increased the substrate saturability of glucose transport. Furthermore, cytochalasin B binding to membranes prepared by using less centrifugation time than usual showed that, after stimulation with insulin and contractions, at least 35% of the total number of glucose transporters were redistributed from one kind of vesicles to a more slowly sedimenting kind of vesicles, probably reflecting translocation within the membrane preparation from intracellular vesicles to the plasma membrane upon stimulation. In the present membrane preparation the effects of insulin and/or contractions on glucose transport resemble those seen in intact muscle, and the effects are thus not dependent on cellular integrity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of phenylarsine oxide on stimulation of glucose transport in rat skeletal muscle

1990 ◽  
Vol 258 (4) ◽  
pp. C648-C653 ◽  
Author(s):  
E. J. Henriksen ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Cytochalasin B ◽  
Contractile Activity ◽  
Transport Activity ◽  
Rat Skeletal Muscle ◽  
Phenylarsine Oxide ◽  
Muscle Glucose Transport ◽  
Glucose Analogue ◽  
Stimulation Of

The trivalent arsenical phenylarsine oxide (PAO) inhibits insulin-stimulated glucose transport in adipocytes and skeletal muscle through direct interactions with vicinal sulfhydryls. In muscle, glucose transport is also activated by contractile activity and hypoxia. It was therefore the purpose of the present study to investigate whether vicinal sulfhydryls are involved in the stimulation of glucose transport activity in the isolated rat epitrochlearis muscle by hypoxia or contractions. PAO (greater than 5 microM) caused a twofold increase in rate of transport of the nonmetabolizable glucose analogue 3-O-methylglucose (3-MG) that was completely prevented by cytochalasin B, the vicinal dithiol dimercaptopropanol, dantrolene, or 9-aminoacridine, both inhibitors of sarcoplasmic reticulum Ca2+ release, or omission of extracellular Ca2+. Although PAO treatment (greater than or equal to 20 microM) prevented approximately 80% of the increase in 3-MG transport caused by insulin, it resulted in only a approximately 50% inhibition of the stimulation of 3-MG transport by either hypoxia or contractile activity. PAO treatment (40 microM) of muscles already maximally stimulated by insulin, contractile activity, or hypoxia did not reverse the enhanced rate of 3-MG transport. These data suggest that vicinal sulfhydryls play a greater role in the activation of glucose transport by insulin than by muscle contractions or hypoxia. The finding that PAO inhibits the stimulation of glucose transport, but does not affect glucose transport after it has been stimulated, provides evidence that vicinal sulfhydryls are involved in the pathways for glucose transport activation in muscle, but not in the glucose transport mechanism itself.

Na+-independent D-glucose transport in rabbit renal basolateral membranes

1988 ◽  
Vol 254 (5) ◽  
pp. F711-F718 ◽  
Author(s):  
P. T. Cheung ◽  
M. R. Hammerman
Keyword(s):  
Glucose Uptake ◽  
Glucose Transport ◽  
Brush Border ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Rabbit Kidney ◽  
Basolateral Membrane Vesicles ◽  
Proximal Tubular

To define the mechanism by which glucose is transported across the basolateral membrane of the renal proximal tubular cell, we measured D-[14C]glucose uptake in basolateral membrane vesicles from rabbit kidney. Na+-dependent D-glucose transport, demonstrable in brush-border vesicles, could not be demonstrated in basolateral membrane vesicles. In the absence of Na+, the uptake of D-[14C]glucose in basolateral vesicles was more rapid than that of L-[3H]glucose over a concentration range of 1-50 mM. Subtraction of the latter from the former uptakes revealed a saturable process with apparent Km of 9.9 mM and Vmax of 0.80 nmol.mg protein-1.s-1. To characterize the transport component of D-glucose uptake in basolateral vesicles, we measured trans stimulation of 2 mM D-[14C]glucose entry in the absence of Na+. Trans stimulation could be effected by preloading basolateral vesicles with D-glucose, 2-deoxy-D-glucose, or 3-O-methyl-D-glucose, but not with L-glucose or alpha-methyl-D-glucoside. Trans-stimulated D-[14C]glucose uptake was inhibited by 0.1 mM phloretin or cytochalasin B but not phlorizin. In contrast, Na+-dependent D-[14C]glucose transport in brush-border vesicles was inhibited by phlorizin but not phloretin or cytochalasin B. Our findings are consistent with the presence of a Na+-independent D-glucose transporter in the proximal tubular basolateral membrane with characteristics similar to those of transporters present in nonepithelial cells.

Discrepancy between glucose transport and transporters in human femoral adipocytes

1989 ◽  
Vol 256 (1) ◽  
pp. E179-E185 ◽  
Author(s):  
E. Karnieli ◽  
R. Moscona ◽  
R. Rafaeloff ◽  
Y. G. Illouz ◽  
M. Armoni
Keyword(s):  
Glucose Transport ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Intact Cell ◽  
Transport Activity ◽  
Intact Cells ◽  
Insulin Resistant ◽  
Large Size ◽  
Microsomal Membranes ◽  
Subcutaneous Adipose

Obesity is known to be associated with insulin resistance in human and rat adipocytes. However, it is not known what are the perturbations in insulin action that contribute to disproportional femoral obesity. Thus femoral subcutaneous adipose tissue was obtained from lean women with various degrees of disproportional obesity, by liposuction. 3-O-methylglucose (3-O-methyl-D-glucopyranose) transport was measured in intact cells, and glucose transporter levels in plasma and low-density microsomal membranes were assessed using the cytochalasin B binding assay. A sixfold cellular enlargement was associated with increase in both basal and insulin-stimulated glucose transport activity in the intact cell, and a 300-600% increase in insulin stimulating effect per se. However, when glucose transporter levels were assessed, this cellular enlargement was accompanied by a 40-70% transporter depletion (in largest cells compared with smallest ones) in both subcellular fractions examined, from either basal or insulin-stimulated cells. This discrepancy, between increasing cellular glucose transport rates and relative depletion of transporter levels, suggests that these cells are not insulin resistant, as could be expected from their large size. A role for other factor(s), additional to glucose transporter levels, in the regulation of cellular glucose uptake rate is thus suggested.

scholarly journals Analysis of the structural features of the C-terminus of GLUT1 that are required for transport catalytic activity

1995 ◽  
Vol 311 (2) ◽  
pp. 699-704 ◽  
Author(s):  
A Muraoka ◽  
M Hashiramoto ◽  
A E Clark ◽  
L C Edwards ◽  
H Sakura ◽  
...  
Keyword(s):  
Amino Acids ◽  
Glucose Transport ◽  
Cytochalasin B ◽  
Point Mutations ◽  
Chinese Hamster ◽  
Structural Features ◽  
Transport Activity ◽  
Wild Type ◽  
C Terminus ◽  
Wild Type Clone

C-terminally truncated and mutated forms of GLUT1 have been constructed to determine the minimum structure at the C-terminus required for glucose transport activity and ligand binding at the outer and inner binding sites. Four truncated mutants have been constructed (CTD24 to CTD27) in which 24 to 27 amino acids are deleted. In addition, point substitutions of R468-->L, F467-->L and G466-->E have been produced. Chinese hamster ovary clones which were transfected with these mutant GLUT1s were shown, by Western blotting and cell-surface carbohydrate labelling, to have expression levels which were comparable with the wild-type clone. Wild-type levels of 2-deoxy-D-glucose transport activity were retained only in the clone transfected with the construct in which 24 amino acids were deleted (CTD24). The CTD25, CTD26 and CTD27 clones showed markedly reduced transport activity. From a kinetic comparison of the CTD24 and CTD26 clones it was found that the reduced transport was mainly associated with a reduced Vmax. value for 2-deoxy-D-glucose uptake but with a slight lowering of the Km. These data establish that the 24 amino acids at the C-terminus of GLUT1 are not required for the transport catalysis. However, the point mutations of F467L and G466E (26 and 27 residues from the C-terminus) did not significantly perturb the kinetics of 2-deoxy-D-glucose transport. The substitution of R468L produced a slight, but significant, lowering of the Km. The ability of the truncated GLUt1s to bind the exofacial ligand, 2-N-4-(1-zai-2,2,2-trifluoroethyl)benzoyl-1,3-bis-(D-mannos- 4-yl-oxy) -2-propylamine (ATB-BMPA), and the endofacial ligand, cytochalasin B, were assessed by photolabelling procedures. The ability to bind ATB-BMPA was retained only in the CTD24 truncated mutant and was reduced to levels comparable with those of the non-transfected clone in the other mutant clones. Cytochalasin B labelling was unimpaired in all four mutated GLUT1s. These data establish that a minimum structure at the C-terminus of GLUT1, which is required for the conformational change to expose the exofacial site, includes amino acids at positions Phe-467 and Arg-468; however, these amino acids are not individually essential.

scholarly journals Caffeine inhibits glucose transport by binding at the GLUT1 nucleotide-binding site

2015 ◽  
Vol 308 (10) ◽  
pp. C827-C834 ◽  
Author(s):  
Jay M. Sage ◽  
Anthony J. Cura ◽  
Kenneth P. Lloyd ◽  
Anthony Carruthers
Keyword(s):  
Binding Site ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Sugar Transport ◽  
Nucleotide Binding ◽  
Nucleotide Binding Site ◽  
Sugar Uptake ◽  
Glucose Transporter 1 ◽  
Intracellular Atp

Glucose transporter 1 (GLUT1) is the primary glucose transport protein of the cardiovascular system and astroglia. A recent study proposes that caffeine uncompetitive inhibition of GLUT1 results from interactions at an exofacial GLUT1 site. Intracellular ATP is also an uncompetitive GLUT1 inhibitor and shares structural similarities with caffeine, suggesting that caffeine acts at the previously characterized endofacial GLUT1 nucleotide-binding site. We tested this by confirming that caffeine uncompetitively inhibits GLUT1-mediated 3- O-methylglucose uptake in human erythrocytes [ Vmax and Km for transport are reduced fourfold; Ki(app) = 3.5 mM caffeine]. ATP and AMP antagonize caffeine inhibition of 3- O-methylglucose uptake in erythrocyte ghosts by increasing Ki(app) for caffeine inhibition of transport from 0.9 ± 0.3 mM in the absence of intracellular nucleotides to 2.6 ± 0.6 and 2.4 ± 0.5 mM in the presence of 5 mM intracellular ATP or AMP, respectively. Extracellular ATP has no effect on sugar uptake or its inhibition by caffeine. Caffeine and ATP displace the fluorescent ATP derivative, trinitrophenyl-ATP, from the GLUT1 nucleotide-binding site, but d-glucose and the transport inhibitor cytochalasin B do not. Caffeine, but not ATP, inhibits cytochalasin B binding to GLUT1. Like ATP, caffeine renders the GLUT1 carboxy-terminus less accessible to peptide-directed antibodies, but cytochalasin B and d-glucose do not. These results suggest that the caffeine-binding site bridges two nonoverlapping GLUT1 endofacial sites—the regulatory, nucleotide-binding site and the cytochalasin B-binding site. Caffeine binding to GLUT1 mimics the action of ATP but not cytochalasin B on sugar transport. Molecular docking studies support this hypothesis.

Stimulation of glucose transport in skeletal muscle by hypoxia

1991 ◽  
Vol 70 (4) ◽  
pp. 1593-1600 ◽  
Author(s):  
G. D. Cartee ◽  
A. G. Douen ◽  
T. Ramlal ◽  
A. Klip ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Muscle Contraction ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Sugar Transport ◽  
Transport Activity ◽  
Hindlimb Muscles ◽  
Stimulation Of

Hypoxia caused a progressive cytochalasin B-inhibitable increase in the rate of 3-O-methylglucose transport in rat epitrochlearis muscles to a level approximately six-fold above basal. Muscle ATP concentration was well maintained during hypoxia, and increased glucose transport activity was still present after 15 min of reoxygenation despite repletion of phosphocreatine. However, the increase in glucose transport activity completely reversed during a 180-min-long recovery in oxygenated medium. In perfused rat hindlimb muscles, hypoxia caused an increase in glucose transporters in the plasma membrane, suggesting that glucose transporter translocation plays a role in the stimulation of glucose transport by hypoxia. The maximal effects of hypoxia and insulin on glucose transport activity were additive, whereas the effects of exercise and hypoxia were not, providing evidence suggesting that hypoxia and exercise stimulate glucose transport by the same mechanism. Caffeine, at a concentration too low to cause muscle contraction or an increase in glucose transport by itself, markedly potentiated the effect of a submaximal hypoxic stimulus on sugar transport. Dantrolene significantly inhibited the hypoxia-induced increase in 3-O-methylglucose transport. These effects of caffeine and dantrolene suggest that Ca2+ plays a role in the stimulation of glucose transport by hypoxia.

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