scholarly journals Sodium-bicarbonate cotransport occurs in rat kidney cortical membranes but not in rat small intestinal basolateral membranes

1987 ◽  
Vol 246 (2) ◽  
pp. 543-545 ◽  
Author(s):  
B Hagenbuch ◽  
G Stange ◽  
H Murer
Keyword(s):  
Rat Kidney ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Kidney Cortex ◽  
Sodium Influx ◽  
Rat Kidney Cortex ◽  
Basolateral Membranes ◽  
Small Intestinal ◽  
Cortical Membranes ◽  
Intestinal Enterocytes

Basolateral membrane vesicles were isolated from rat kidney cortex and small intestinal enterocytes. Both membrane preparations show ATP-dependent calcium uptake and cytochalasin B-sensitive D-glucose transport. In renal membranes, sodium influx is stimulated by bicarbonate; bicarbonate-dependent sodium flux is membrane-potential-dependent and inhibited by 4,4′-di-isothiocyanato-2, 2′-stilbenedisulphanic acid (‘DIDS’). Small intestinal basolateral membranes do not show bicarbonate-dependent sodium fluxes.

Inhibition by phenylglyoxal of the sodium-coupled fluxes of glucose and phosphate in renal brush-border membranes

1988 ◽  
Vol 66 (9) ◽  
pp. 1005-1012 ◽  
Author(s):  
R. Béliveau ◽  
M. Bernier ◽  
S. Giroux ◽  
D. Bates
Keyword(s):  
Brush Border ◽  
Direct Method ◽  
Rat Kidney ◽  
Membrane Vesicles ◽  
Kidney Cortex ◽  
Sodium Influx ◽  
Rat Kidney Cortex ◽  
Process Modification ◽  
Arginine Residues ◽  
Phosphate Influx

The coupling of phosphate and glucose transport to sodium in brush-border membrane vesicles from rat kidney cortex was studied after chemical modification of arginine residues by phenylglyoxal. Phosphate (10 mM) and sodium (20 mM) uptakes were linear for 6 s and stimulated in the presence of their cosubstrate. The sodium: phosphate stoichiometry measured by a direct method was 1.74. Sodium-independent phosphate and glucose influx were found to be unaffected by phenylglyoxylation. Phosphate- or glucose-independent sodium influx also remained unaltered by the treatment. However, phosphate influx measured with sodium was inhibited by 69% and sodium influx measured with phosphate was inhibited by 40%. When these values were corrected for uncoupled fluxes, the sodium influx coupled to phosphate and the phosphate influx coupled to sodium were inhibited by 93 and 95%, respectively. Glucose influx measured in the presence of sodium was inhibited by 36% and sodium influx in the presence of glucose was reduced by 39%. When the values were corrected for diffusion, these inhibitions were 95 and 100%, respectively. We conclude that the coupling of phosphate and glucose to sodium fluxes by the renal carriers requires the participation of arginine residue(s) in the translocation process. Modification of this arginine by phenylglyoxal leads to a marked inhibition of coupling. These results suggest the implication of arginine residues in the molecular coupling for both glucose and phosphate sodium symporters.

Indirect coupling to Na+ of p-aminohippuric acid uptake into rat renal basolateral membrane vesicles

1987 ◽  
Vol 253 (5) ◽  
pp. F795-F801 ◽  
Author(s):  
H. Shimada ◽  
B. Moewes ◽  
G. Burckhardt
Keyword(s):  
Transport System ◽  
Equilibrium Distribution ◽  
Rat Kidney ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Kidney Cortex ◽  
Acid Uptake ◽  
Basolateral Membrane Vesicles ◽  
Rat Kidney Cortex ◽  
Indirect Coupling

Experiments with basolateral membrane vesicles prepared from rat kidney cortex were performed to study the mechanism by which p-aminohippuric acid (PAH) is taken up across the contraluminal membrane and is concentrated in proximal tubule cells. An inward Na+ gradient failed to stimulate [3H]PAH uptake compared with K+ or Li+ and did not cause intravesicular PAH accumulation above equilibrium distribution. In the absence of Na+, the dicarboxylates glutarate and suberate cis-inhibited and trans-stimulated [3H]PAH uptake, indicating a common transport system. In the presence of Na+, 10 microM glutarate in the incubation medium did not cis-inhibit, but rather stimulated [3H]PAH uptake and caused PAH accumulation above equilibrium distribution ("overshoot"). Li+ diminished this stimulation, but was without effect on [3H]PAH/PAH- and [3H]PAH/glutarate exchange. The data indicate the coexistence of a Na+ -coupled, Li+-sensitive transport system for dicarboxylates and a Li+ -insensitive PAH/dicarboxylate exchanger in the basolateral membrane. We propose that dicarboxylates are cotransported with Na+ into the cell and subsequently exchange for extracellular PAH at the basolateral membrane. PAH uptake is thereby indirectly coupled to Na+ via the Na+/dicarboxylate cotransporter.

ATP-dependent H+ pump in membrane vesicles from rat kidney cortex

1985 ◽  
Vol 248 (6) ◽  
pp. F835-F844 ◽  
Author(s):  
I. Sabolic ◽  
W. Haase ◽  
G. Burckhardt
Keyword(s):  
Horseradish Peroxidase ◽  
Brush Border ◽  
Rat Kidney ◽  
Membrane Vesicles ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Basolateral Membranes ◽  
Brush Border Membranes ◽  
Endocytotic Vesicles

The presence of membrane vesicles containing an ATP-driven H+ pump was demonstrated in rat kidney cortex homogenate using the delta pH-sensitive dye acridine orange (AO). These vesicles were purified by differential and Percoll density gradient centrifugation. ATP-driven H+ uptake was about 20-fold enriched compared with the homogenate. Determination of marker enzyme activities indicated that these vesicles do not originate from brush border and basolateral membranes, lysosomes, endoplasmic reticulum, mitochondria, Golgi membranes, or red blood cells. The identity with brush border membranes was further excluded by the absence of Na+-H+ exchange. Renal cortical endocytotic vesicles that had taken up horseradish peroxidase or fluorescein isothiocyanate-labeled dextran (FITC-dextran) after injection of these substances into rats in vivo comigrated with the H+ pump activity on the Percoll gradient. Similar characteristics of the H+ pump demonstrated by the AO method and by fluorescence changes of in vivo trapped FITC-dextran proved the identity of H+ pump-containing vesicles with endocytotic vesicles. ATP-driven H+ uptake into endocytotic vesicles was stimulated by Cl- and weakly inhibited by oligomycin. N-ethylmaleimide, dicyclohexylcarbodiimide, and Dio-9 were stronger inhibitors. Histochemical studies revealed that horseradish peroxidase-filled endocytotic vesicles are localized in the apical region of proximal tubule cells. An H+ pump with similar characteristics, but much lower activity, was found in brush border membranes, basolateral membranes, and mitochondria isolated by standard techniques, suggesting a possible contamination of these preparations with endocytotic vesicles.

scholarly journals Na+-gradient-dependent stimulation of renal transport of ρ-aminohippurate

1982 ◽  
Vol 208 (1) ◽  
pp. 243-246 ◽  
Author(s):  
M I Sheikh ◽  
J V Møller
Keyword(s):  
Rat Kidney ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Cortex Slices ◽  
Kidney Cortex Slices ◽  
Stimulation Of

Transport of rho-aminohippurate was studied by the use of a preparation of rabbit kidney basolateral-membrane vesicles and in rat kidney-cortex slices under anaerobic conditions. With both preparations clear evidence of Na+-gradient stimulation of rho-aminohippurate transport (‘overshoot’) was obtained. These results thus indicate that a significant aspect of active rho-aminohippurate transport is by co-transport with Na+, and they appear to resolve previous disagreements concerning the role of Na+. Vesicle studies with a potential-sensitive dye suggested that rho-aminohippurate may be transported electroneutrally, i.e. in a 1:1 complex with Na+.

scholarly journals Studies on the orientation of brush-border membrane vesicles

1978 ◽  
Vol 172 (1) ◽  
pp. 57-62 ◽  
Author(s):  
W Haase ◽  
A Schäfer ◽  
H Murer ◽  
R Kinne
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Rat Kidney ◽  
Freeze Fracture ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Immunological Methods ◽  
Kidney Cortex ◽  
Asymmetric Distribution ◽  
Rat Kidney Cortex

Orientation of rat renal and intestinal brush-border membrane vesicles was studied with two independent methods: electron-microscopic freeze-fracture technique and immunological methods. With the freeze-fracture technique a distinct asymmetric distribution of particles on the two membrane fracture faces was demonstrated; this was used as a criterion for orientation of the isolated membrane vesicles. For the immunological approach the accessibility or inaccessibility of aminopeptidase M localized on the outer surface of the cell membrane to antibodies was used. With both methods we showed that the brush-border membrane vesicles isolated from rat kidney cortex and from rat small intestine for transport studies are predominantly orientated right-side out.

scholarly journals pH gradient as an additional driving force in the renal re-absorption of phosphate

1990 ◽  
Vol 271 (3) ◽  
pp. 687-692 ◽  
Author(s):  
J Strévey ◽  
S Giroux ◽  
R Béliveau
Keyword(s):  
Driving Force ◽  
Phosphate Uptake ◽  
Rat Kidney ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Total Phosphate Concentration ◽  
Combined Action ◽  
Phosphate Carrier

The effects of the Na+ gradient and pH on phosphate uptake were studied in brush-border membrane vesicles isolated from rat kidney cortex. The initial rates of Na(+)-dependent phosphate uptake were measured at pH 6.5, 7.5 and 8.5 in the presence of sodium gluconate. At a constant total phosphate concentration, the transport values at pH 7.5 and 8.5 were similar, but at pH 6.5 the influx was 31% of that at pH 7.5. However, when the concentration of bivalent phosphate was kept constant at all three pH values, the effect of pH was less pronounced; at pH 6.5, phosphate influx was 73% of that measured at pH 7.5. The Na(+)-dependent phosphate uptake was also influenced by a transmembrane pH difference; an outwardly directed H+ gradient stimulated the uptake by 48%, whereas an inwardly directed H+ gradient inhibited the uptake by 15%. Phosphate on the trans (intravesicular) side stimulated the Na(+)-gradient-dependent phosphate transport by 59%, 93% and 49%, and the Na(+)-gradient-independent phosphate transport by 240%, 280% and 244%, at pH 6.5, 7.5 and 8.5 respectively. However, in both cases, at pH 6.5 the maximal stimulation was seen only when the concentration of bivalent trans phosphate was the same as at pH 7.5. In the absence of a Na+ gradient, but in the presence of Na+, an outwardly directed H+ gradient provided the driving force for the transient hyperaccumulation of phosphate. The rate of uptake was dependent on the magnitude of the H+ gradient. These results indicate that: (1) the bivalent form of phosphate is the form of phosphate recognized by the carrier on both sides of the membrane; (2) protons are both activators and allosteric modulators of the phosphate carrier; (3) the combined action of both the Na+ (out/in) and H+ (in/out) gradients on the phosphate carrier contribute to regulate efficiently the re-absorption of phosphate.

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