Sodium-dependent chloride transport in basolateral membrane vesicles isolated from rabbit proximal tubule

Biochemistry ◽  
1988 ◽  
Vol 27 (2) ◽  
pp. 655-660 ◽  
Author(s):  
Pei Yuan Chen ◽  
A. S. Verkman
Keyword(s):  
Proximal Tubule ◽  
Chloride Transport ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Basolateral Membrane Vesicles ◽  
Sodium Dependent

Urate transport in the proximal tubule: in vivo and vesicle studies

1985 ◽  
Vol 249 (6) ◽  
pp. F789-F798 ◽  
Author(s):  
A. M. Kahn ◽  
E. J. Weinman
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Anion Exchanger ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Transport Processes ◽  
Basolateral Membrane Vesicles ◽  
Urate Transport ◽  
Rat Proximal Tubule

The transport of urate in the mammalian nephron is largely confined to the proximal tubule. Depending on the species, net reabsorption or net secretion is observed. The rat, like the human and the mongrel dog, demonstrates net reabsorption of urate and has been the most extensively studied species. The unidirectional reabsorption and secretion of urate in the rat proximal tubule occur via a passive and presumably paracellular route and by a mediated transcellular route. The reabsorption of urate, and possibly its secretion, can occur against an electrochemical gradient. A variety of drugs and other compounds affect the reabsorption and secretion of urate. The effects of these agents depend on their site of application (luminal or blood), concentration, and occasionally their participation in transport processes that do not have affinity for urate. Recent studies with renal brush border and basolateral membrane vesicles from the rat and brush border vesicles from the dog have determined the mechanisms for urate transport across the luminal and antiluminal membranes of the proximal tubule cell. Brush border membrane vesicles contain an anion exchanger with affinity for urate, hydroxyl ion, bicarbonate, chloride, lactate, p-aminohippurate (PAH), and a variety of other organic anions. Basolateral membrane vesicles contain an anion exchanger with affinity for urate and chloride but not for PAH. Both membrane vesicle preparations also permit urate translocation by simple diffusion. A model for the transcellular reabsorption and secretion of urate in the rat proximal tubule is proposed. This model is based on the vesicle studies, and it can potentially explain the majority of urate transport data obtained with in vivo techniques.

Chloride Transport Across Rat Ileal Basolateral Membrane Vesicles

1992 ◽  
Vol 201 (3) ◽  
pp. 254-260 ◽  
Author(s):  
M. Daher ◽  
S. Acra ◽  
W. Dykes ◽  
F. K. Ghishan
Keyword(s):  
Chloride Transport ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Basolateral Membrane Vesicles

Indirect Na+ dependency of urate and p-aminohippurate transport in pig basolateral membrane vesicles

1991 ◽  
Vol 261 (2) ◽  
pp. F265-F272 ◽  
Author(s):  
D. Werner ◽  
F. Roch-Ramel
Keyword(s):  
Proximal Tubule ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Organic Anions ◽  
Transport Processes ◽  
Basolateral Membrane Vesicles ◽  
Pig Kidney ◽  
Different Characteristics ◽  
Stimulation Of

Membrane vesicles were used to study the basolateral transport of urate and p-aminohippurate (PAH) in the proximal tubule of the pig kidney. Consistent with a cooperation between a Na(+)-2-oxoglutarate cotransporter and a 2-oxoglutarate-urate or a 2-oxoglutarate-PAH exchanger, urate and PAH uptakes were stimulated in presence of extravesicular 2-oxoglutarate when an inwardly directed Na+ gradient was applied. Both transports exhibited, however, different characteristics. The optimal 2-oxoglutarate concentration for stimulating uptakes was 10 microM for PAH and 150 microM for urate. Extravesicular chloride was required to observe a stimulation of PAH uptake but not of urate uptake. Transports of both PAH and urate exhibited different affinity sequences for various organic anions. Stimulated PAH uptake was inhibited by probenecid greater than cold PAH greater than urate = pyrazinoate greater than lactate, whereas stimulated urate uptake was inhibited by probenecid greater than cold urate greater than PAH and not by pyrazinoate or lactate. These results are consistent with independent transport processes for urate and PAH in pig basolateral membrane vesicles, both being indirectly driven by an inwardly directed Na+ gradient.

scholarly journals l-tryptophan uptake by segment-specific membrane vesicles from the proximal tubule of rabbit kidney

1992 ◽  
Vol 286 (1) ◽  
pp. 103-110 ◽  
Author(s):  
H Jessen ◽  
M I Sheikh
Keyword(s):  
Proximal Tubule ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Rabbit Kidney ◽  
Basolateral Membrane Vesicles ◽  
Luminal Membrane ◽  
Transport Component ◽  
Pars Recta ◽  
Dependent Transport ◽  
Pars Convoluta

1. The mechanism of the renal transport of L-tryptophan by basolateral and luminal membrane vesicles prepared from either the pars convoluta or the pars recta of the rabbit proximal tubule was studied. The uptake of L-tryptophan by basolateral membrane vesicles from the pars convoluta was found to be an Na(+)-dependent transport event. The Na(+)-conditional influx of the amino acid was stimulated in the presence of an inwardly directed H+ gradient. Lowering the pH without an H+ gradient had no effect, indicating that L-tryptophan is co-transported with H+. 3. On the other hand, no transient accumulation of L-tryptophan was observed in the presence or absence of Na+ in basolateral membrane vesicles from the pars recta. 4. In luminal membrane vesicles from the pars recta, the transient Na(+)-dependent accumulation of L-tryptophan occurred via a dual transport system. In addition, an inwardly directed H+ gradient could drive the uphill transport of L-tryptophan into these vesicles in both the presence and the absence of an Na+ gradient. 5. By contrast, the uptake of L-tryptophan by luminal membrane vesicles from the pars convoluta was a strictly Na(+)-dependent and electrogenic transport process, mediated by a single transport component. 6. Investigation of the coupling ratio in luminal membrane vesicles suggested that 1 Na+:1 L-tryptophan are co-transported in the pars convoluta. In the pars recta, examination of the stoichiometry indicated that approx. 1 H+ and 2 Na+ (high affinity) or 1 Na+ (low affinity) are involved in the uptake of L-tryptophan.

Urate/α-ketoglutarate exchange in avian basolateral membrane vesicles

2002 ◽  
Vol 283 (4) ◽  
pp. C1144-C1154 ◽  
Author(s):  
Steven M. Grassl
Keyword(s):  
Proximal Tubule ◽  
Brush Border Membrane ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Basolateral Membrane Vesicles ◽  
Transport Pathways ◽  
Proximal Tubule Cells ◽  
Flux Measurements ◽  
Avian Kidney ◽  
Sufficient Magnitude

Membrane transport pathways for transcellular secretion of urate across the proximal tubule were investigated in avian kidney. The presence of coupled urate/α-ketoglutarate exchange was investigated in basolateral membrane vesicles (BLMV) by [14C]urate and [α-3H]ketoglutarate flux measurements. An inward Na gradient induced accumulation of α-ketoglutarate of sufficient magnitude to suggest a Na-dicarboxylate cotransporter. An inward Na gradient also induced concentrative accumulation of urate in the presence of α-ketoglutarate but not in its absence, suggesting urate/α-ketoglutarate exchange. α-Ketoglutarate-dependent stimulation of urate uptake was not observed in brush-border membrane vesicles. An outward urate gradient induced concentrative accumulation of α-ketoglutarate. α-Ketoglutarate-coupled urate uptake was specific for α-ketoglutarate, Cl dependent, and insensitive to membrane potential. α-Ketoglutarate-coupled urate uptake was inhibited by increasing p-aminohippurate (PAH) concentrations, and α-ketoglutarate-coupled PAH uptake was observed. α-Ketoglutarate-coupled PAH uptake was inhibited by increasing urate concentrations, and an outward urate gradient induced concentrative accumulation of PAH. These results suggest a Cl-dependent, α-ketoglutarate-coupled anion exchange mechanism as a pathway for active urate uptake across the basolateral membrane of urate-secreting proximal tubule cells.

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