Comparison of glucose transport mechanisms at opposing surfaces of the renal proximal tubular cell

1986 ◽  
Vol 64 (11) ◽  
pp. 1092-1098 ◽  
Author(s):  
M. Silverman
Keyword(s):  
Glucose Transport ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Glucose Transporter ◽  
Sugar Transport ◽  
Point Of View ◽  
Transport Mechanisms ◽  
Proximal Tubular ◽  
Renal Proximal Tubular

This review contrasts the glucose transport mechanisms at opposing surfaces of the renal proximal convoluted tubule: the Na+-dependent D-glucose transporter localized at the brush border membrane and the Na+-independent transporter localized at the basolateral surface. The two sugar transport mechanisms are discussed from the point of view of their specificity, kinetic, and regulatory behaviors. Recent results focussing on molecular characterization of these different carrier proteins are also described, including some newer information on purification of the Na+-dependent glucose carrier from the brush border membrane.

Enhancement of Gentamicin-Induced Inhibition of Phosphatidylinositol Hydrolysis in Rabbit Renal Proximal Tubular Brush-Border Membrane by Furosemide

Renal Failure ◽  
1989 ◽  
Vol 11 (2-3) ◽  
pp. 105-109 ◽  
Author(s):  
Hajime Nakahama ◽  
SungHyo Shin ◽  
Toshiki Moriyama ◽  
Masahiro Kakihara ◽  
Yoshifumi Fukuhara ◽  
...  
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Proximal Tubular ◽  
Renal Proximal Tubular

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.

Characterization of d-Glucose Transport across Equine Jejunal Brush Border Membrane Using the Pig as an Efficient Model of Jejunal Glucose Uptake

2013 ◽  
Vol 33 (6) ◽  
pp. 460-467 ◽  
Author(s):  
Adrienne D. Woodward ◽  
Ming Z. Fan ◽  
Raymond J. Geor ◽  
Laura J. McCutcheon ◽  
Nathanael P. Taylor ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Transport ◽  
Brush Border ◽  
Brush Border Membrane

scholarly journals Transepithelial glucose transport in the small intestine

2020 ◽  
Vol 51 (6) ◽  
pp. 673-686
Author(s):  
Mirela Pavić ◽  
Marija Ljubojević ◽  
Ivona Žura Žaja ◽  
Ivana Prakatur ◽  
Manuela Grčević ◽  
...  
Keyword(s):  
Small Intestine ◽  
Glucose Transport ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Glucose Transporter ◽  
Enzymatic Digestion ◽  
Transepithelial Transport ◽  
Facilitated Diffusion ◽  
Glucose Transporter 2 ◽  
Complex Carbohydrates

The duodenum, jejunum and ileum are parts of the small intestine and the sites of the terminal stages of enzymatic digestion, and the majority of nutrient, electrolyte and water absorption. The apical, luminal membrane of the enterocyte is built of numerous microvilli that increase the absorptive surface of the cell. Carbohydrates, in the form of monosaccharides, oligosaccharides and especially polysaccharides, make up the largest quantitative and energetic part of the diet of most animals, including humans. Galactose, fructose and glucose, the final degradation products of polysaccharide and oligosaccharide enzymatic digestion, can be absorbed by enterocytes either by active transport or by facilitated diffusion. In the small intestine, the transepithelial transport of glucose, the most abundant monosaccharide after carbohydrate digestion and the main source of energy, is performed by a specific membrane transporter located in the brush border membrane of the enterocyte, the sodiumglucose cotransporter 1 (SGLT1). While SGLT1 transports glucose across the brush border membrane, a specific basolateral membrane glucose transporter, the sodium-independent glucose transporter 2 (GLUT2), transfers glucose out of the enterocyte down the concentration gradient. The sodium-potassium pump (Na/KATPase), as a sodium and potassium ion transporter, is functionally closely related to the sodium-dependent SGLT1. Na/KATPase is responsible for maintaining the electrochemical gradient of sodium ions, as the driving force for glucose transport via SGLT1. Transepithelial transport of glucose in the small intestine and the differentiation of enterocytes occurs relatively early during the foetal period, allowing glucose to be absorbed from ingested amniotic fluid. Nutrient transport is possible along the whole villus-crypt axis during intrauterine development, while transport shifts toward the villus tip in the mature small intestine. With maturation, glucose transport rates change not only across the villus-crypt axis, but also along the proximodistal axis in the small intestine. The glucose absorption rate shows differences between subunits of the small intestine depending on the age and type of ingested carbohydrates, where complex carbohydrates replace less complex carbohydrates or disaccharides.

Effect of acute acidemia on phosphate uptake by renal proximal tubular brush-border membranes

1986 ◽  
Vol 251 (5) ◽  
pp. F889-F896
Author(s):  
B. S. Levine ◽  
J. A. Kraut ◽  
D. R. Mishler ◽  
P. W. Crooks
Keyword(s):  
Metabolic Acidosis ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Respiratory Acidosis ◽  
Tissue Slices ◽  
Pi Transport ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Plasma Phosphorus

Prolonged metabolic acidosis is associated with depressed phosphate (Pi) uptake by the brush-border membrane (BBM) of the proximal tubule. To examine if changes in systemic pH underlie this inhibition, we measured Pi transport by renal cortical BBM from thyroparathyroidectomized rats with respiratory or metabolic acidosis of 1 or 3 h, respectively, and in appropriate controls. Also, Pi transport was measured in BBM prepared using tissue slices from nonacidotic rats that were preincubated for 20 or 45 min at either pH 6.9 (HCO3 = 10 mM, CO2 = 10%) or 7.4 (HCO3 = 10 mM, CO2 = 2.5%). Despite comparable acidemia (pH 7.06 +/- 0.05 with respiratory acidosis and 7.10 +/- 0.03 with metabolic acidosis), Na-dependent Pi uptake at 5 s incubation was reduced by 15.2 +/- 3.5% with respiratory acidosis compared with paired controls. It was not altered with metabolic acidosis. Vmax in respiratory acidosis (1.2 nmol X mg protein-1 X 5 s-1) was less than in controls (1.6); Kt was similar in both groups. 22Na transport and Na-dependent glucose transport were unchanged. Plasma phosphorus (P) increased from 8.75 +/- 0.35 mg/dl to 12.42 +/- 1.9 with respiratory acidosis. Therefore BBM vesicles transport was measured in controls after plasma P was raised. Under these conditions, Pi transport was similar to that with respiratory acidosis. Also Pi transport by BBM was unchanged when tissue slices were preincubated in vitro at high CO2 concentrations for 20 or 45 min. Thus respiratory acidosis specifically inhibits Na-dependent Pi transport by decreasing the number or rate of the BBM Pi carrier.(ABSTRACT TRUNCATED AT 250 WORDS)

Proximal Tubular Phosphate Reabsorption: Molecular Mechanisms

2000 ◽  
Vol 80 (4) ◽  
pp. 1373-1409 ◽  
Author(s):  
Heini Murer ◽  
Nati Hernando ◽  
Ian Forster ◽  
Jürg Biber
Keyword(s):  
Brush Border ◽  
Molecular Mechanisms ◽  
Brush Border Membrane ◽  
Cell Model ◽  
Expression System ◽  
Cellular Mechanisms ◽  
Membrane Expression ◽  
Renal Brush Border Membrane ◽  
Proximal Tubular ◽  
Renal Proximal Tubular

Renal proximal tubular reabsorption of Pi is a key element in overall Pi homeostasis, and it involves a secondary active Pi transport mechanism. Among the molecularly identified sodium-phosphate (Na/Pi) cotransport systems a brush-border membrane type IIa Na-Pi cotransporter is the key player in proximal tubular Pi reabsorption. Physiological and pathophysiological alterations in renal Pi reabsorption are related to altered brush-border membrane expression/content of the type IIa Na-Picotransporter. Complex membrane retrieval/insertion mechanisms are involved in modulating transporter content in the brush-border membrane. In a tissue culture model (OK cells) expressing intrinsically the type IIa Na-Pi cotransporter, the cellular cascades involved in “physiological/pathophysiological” control of Pi reabsorption have been explored. As this cell model offers a “proximal tubular” environment, it is useful for characterization (in heterologous expression studies) of the cellular/molecular requirements for transport regulation. Finally, the oocyte expression system has permitted a thorough characterization of the transport characteristics and of structure/function relationships. Thus the cloning of the type IIa Na-Pi cotransporter (in 1993) provided the tools to study renal brush-border membrane Na-Pi cotransport function/regulation at the cellular/molecular level as well as at the organ level and led to an understanding of cellular mechanisms involved in control of proximal tubular Pi handling and, thus, of overall Pihomeostasis.

Unraveling the Inhibition of Intestinal Glucose Transport by Dietary Phenolics: A Review

2019 ◽  
Vol 25 (32) ◽  
pp. 3418-3433 ◽  
Author(s):  
Joana Pico ◽  
Mario M. Martínez
Keyword(s):  
Glucose Transport ◽  
Brush Border ◽  
Glucose Concentration ◽  
Metabolic Regulation ◽  
Brush Border Membrane ◽  
Glucose Transporter ◽  
Basolateral Membrane ◽  
Glucose Transporters ◽  
Flavonoid Glycosides ◽  
Glucose Response

Background: Glucose transport across the intestinal brush border membrane plays a key role in metabolic regulation. Depending on the luminal glucose concentration, glucose is mainly transported by the sodium- dependent glucose transporter (SGLT1) and the facilitated-transporter glucose transporter (GLUT2). SGLT1 is apical membrane-constitutive and it is active at a low luminal glucose concentration, while at concentrations higher than 50 mM, glucose is mainly transported by GLUT2 (recruited from the basolateral membrane). Dietary phenolic compounds can modulate glucose homeostasis by decreasing the postprandial glucose response through the inhibition of SGLT1 and GLUT2. Methods: Phenolic inhibition of intestinal glucose transport has been examined using brush border membrane vesicles from rats, pigs or rabbits, Xenopus oocytes and more recently Caco-2 cells, which are the most promising for harmonizing in vitro experiments. Results: Phenolic concentrations above 100 µM has been proved to successfully inhibit the glucose transport. Generally, the aglycones quercetin, myricetin, fisetin or apigenin have been reported to strongly inhibit GLUT2, while quercetin-3-O-glycoside has been demonstrated to be more effective in SGLT1. Additionally, epigallocatechin as well as epicatechin and epigallocatechin gallates were observed to be inhibited on both SGLT1 and GLUT2. Conclusion: Although, valuable information regarding the phenolic glucose transport inhibition is known, however, there are some disagreements about which flavonoid glycosides and aglycones exert significant inhibition, and also the inhibition of phenolic acids remains unclear. This review aims to collect, compare and discuss the available information and controversies about the phenolic inhibition of glucose transporters. A detailed discussion on the physicochemical mechanisms involved in phenolics-glucose transporters interactions is also included.

Characterization of D-Glucose Transport across Equine Jejunal Brush Border Membrane Using the Pig as an Efficient Model of Jejunal Glucose Uptake

2011 ◽  
Vol 31 (5-6) ◽  
pp. 280-281 ◽  
Author(s):  
A.D. Woodward ◽  
M.Z. Fan ◽  
J.P. Steibel ◽  
R.J. Goer ◽  
N.P. Taylor ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Transport ◽  
Brush Border ◽  
Brush Border Membrane

Characterization and distribution of albumin binding protein in normal rat kidney

1996 ◽  
Vol 271 (1) ◽  
pp. F101-F107 ◽  
Author(s):  
A. L. Cessac-Guillemet ◽  
F. Mounier ◽  
C. Borot ◽  
H. Bakala ◽  
M. Perichon ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Binding Protein ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Albumin Binding ◽  
Renal Brush Border Membrane ◽  
Proximal Tubular ◽  
Renal Proximal Tubular

The mechanism by which proteins that pass through the glomerular basal lamina are taken up by proximal tubule cells is incompletely characterized. Past work has identified the kinetics of albumin binding to renal brush-border membrane. We have now purified and characterized albumin binding protein (ABP) and shown its distribution in renal proximal tubular cells. ABP was purified from rat renal proximal tubular cell brush-border membrane by affinity chromatography with rat serum albumin-Sepharose. The resulting ABP had two apparent molecular masses (55 and 31 kDa) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antibodies to ABP were raised in rabbits and checked by immunoassay and immunoblotting. Light-microscopic immunohistochemistry showed ABP all along the proximal tubule in the pars convoluta and pars recta. Electron-microscopic immunohistochemistry showed labeling on microvilli and in apical endocytic vacuoles, dense apical tubules, and lysosomes. These results indicate that ABP is involved in proximal tubule endocytosis.

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