Brush border membrane proteins in experimental Fanconi's syndrome induced by 4-pentenoate and maleate

1992 ◽  
Vol 70 (9) ◽  
pp. 1247-1253 ◽  
Author(s):  
Jean-François Pouliot ◽  
André Gougoux ◽  
Richard Béliveau
Keyword(s):  
Protein Phosphorylation ◽  
Brush Border ◽  
Time Course ◽  
Brush Border Membrane ◽  
Transport Systems ◽  
Molecular Defect ◽  
Fanconi’S Syndrome ◽  
Sodium Dependent ◽  
Dependent Transport ◽  
Fanconi's Syndrome

Fanconi's syndrome was investigated using brush border membrane (BBM) vesicles isolated from dog kidney. Sodium-dependent uptake of glucose, phosphate, and amino acids and protein phosphorylation were studied in BBM isolated from normal and from 4-pentenoate- and maleate-treated animals. The time course of D-glucose and phosphate uptake, in BBM vesicles, remained unchanged, indicating that both treatments had no effect on carrier properties, and that permeabilities to these substrates and to sodium were not modified. Furthermore, sodium-dependent transport of alanine, phenylalanine, proline, glycine, and glutamate into vesicles remained unaltered by either treatment. 4-Pentenoate treatment caused modifications of the phosphorylation pattern of BBM proteins: the phosphorylation of two proteins (61 and 74 kDa) was increased and that of two others (48 and 53 kDa) was decreased. Maleate treatment caused an increase in the phosphorylation for the same 61-kDa protein, which was also affected by 4-pentenoate treatment, suggesting that phosphorylation of this protein could be related to a mechanism involved in both 4-pententoate- and maleate-induced Fanconi's syndrome. These changes were also observed in the presence of sodium fluoride and L-bromotetramisole, indicating that the modification of phosphorylation was not due to a difference in phosphatase activities. These results suggest that Fanconi's syndrome induced by 4-pentenoate or maleate is not caused by an inhibition of BBM Na+-dependent transport systems. Our results also suggest that protein phosphorylation may play an important role in the molecular defect involved in Fanconi's syndrome.Key words: Fanconi's syndrome, 4-pentenoate, maleate, transport, phosphorylation.

Age-related changes in sodium-dependent glucose transport in rat small intestine

1986 ◽  
Vol 251 (2) ◽  
pp. G208-G217 ◽  
Author(s):  
H. J. Freeman ◽  
G. A. Quamme
Keyword(s):  
Small Intestine ◽  
Glucose Transport ◽  
Brush Border ◽  
Brush Border Membrane ◽  
High Capacity ◽  
Membrane Vesicles ◽  
Distal Segment ◽  
Brush Border Membrane Vesicles ◽  
Transport Systems ◽  
Sodium Dependent

Brush-border membrane vesicles were purified from jejunoileal segments of rats ranging from 3 to 156 wk. The kinetics of sodium-dependent glucose cotransport were studied under voltage-clamped, zero trans conditions over a wide range of cis-glucose concentrations (0.005-1.5 mM). Initial glucose uptake in brush-border membrane vesicles isolated from the proximal intestinal segment (50 cm from ligament of Treitz) of rats less than 7-8 wk of age demonstrated a distinct curvilinear Hofstee plot consistent with multiple-transport mechanisms. One system possessed an apparent Vmax of 10.6 +/- 0.5 nmol X mg prot-1 X min-1 and Km of 630 +/- 18 microM. The second system was characterized by Vmax of 0.9 +/- 0.1 nmol X mg prot-1 X min-1 and Km of 12 +/- 1 microM. In contrast, the distal segment (50 cm to end of small intestine) possessed only one sodium-dependent glucose carrier system. The apparent Vmax and Km were 1.11 +/- 0.20 nmol X mg protein-1 X min-1 and 49 +/- 7 microM, respectively. Sodium-activation curves in the presence of 0.3 and 0.03 mM glucose were consistent with more than one sodium ion with both systems. In contrast, rats 12-13 wk old and older possessed both sodium-dependent transport systems in the proximal early and distal small intestine. The high-capacity system is more abundant in the proximal than the distal segment. These data suggest that, under these specific conditions, there are two sodium-dependent glucose carriers in the intestine of young rats: one located in the jejunum characterized by high capacity and low affinity, and the second located throughout the jejunoileum characterized by low capacity and high affinity. Furthermore with age there is a development of the low-affinity system in the distal segments so that both systems are found along the length of the jejunum and ileum. Accordingly, serial and parallel heterogeneity of sodium-dependent glucose transport exists along the small intestine.

Distinction between chloride-dependent transport systems for taurine and beta-alanine in rabbit ileum

1992 ◽  
Vol 262 (4) ◽  
pp. G609-G615 ◽  
Author(s):  
L. K. Munck ◽  
B. G. Munck
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Transport Systems ◽  
Rabbit Ileum ◽  
Beta Alanine ◽  
Intestinal Transporter ◽  
Maximal Activation ◽  
Dependent Transport ◽  
Taurine Uptake ◽  
Kinetics Of

This study describes the influx of taurine and beta-alanine across the brush-border membrane of rabbit distal ileum. The kinetics of JmcTau [concentration at which half-maximal activation occurs (K1/2) = 41 microM and Jmax = 24 nmol.cm-2.h-1] are consistent with the kinetics of taurine uptake by jejunal brush-border vesicles. The taurine carrier differs from the beta-alanine carrier by being insensitive to leucine inhibition and by the jejunoileal variation of influx along the small intestine. The K1/2 for sodium and chloride activation of the beta-alanine carrier (48 and 8 mM, respectively) differ markedly from the values reported for the taurine carrier. In addition, taurine is not transported by the beta-alanine carrier. Thus the study demonstrates that the taurine and beta-alanine carriers are separate entities, and it adds to the imino and the taurine carriers the beta-alanine carrier as a third chloride-dependent intestinal transporter of amino acids.

Heterogeneity of sodium-dependent D-glucose transport sites along the proximal tubule: evidence from vesicle studies

1982 ◽  
Vol 242 (4) ◽  
pp. F406-F414 ◽  
Author(s):  
R. J. Turner ◽  
A. Moran
Keyword(s):  
Proximal Tubule ◽  
Glucose Transport ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Kinetic Studies ◽  
Transport Systems ◽  
Rabbit Kidney ◽  
Outer Cortex ◽  
Sodium Dependent

The glucose transport properties of brush border membrane vesicles from the outer cortex (early proximal tubule) and outer medulla (late proximal tubule) of rabbit kidney were studied. In the outer cortical preparation the behavior of the sodium-dependent component of D-glucose flux indicated the presence of a low-affinity transport system with Km congruent to 6 mM and Vmax congruent to 10 nmol.min-1.mg protein-1 as measured under zero trans conditions at 40 mM NaCl and 17 degrees C. By contrast, in the outer medullary preparation this component of flux behaved as a high-affinity system with Km congruent to 0.35 mM and Vmax congruent to 4 nmol.min-1.mg protein-1. Differences in transport specificity between the two preparations were also indicated and glucose uptake by the outer cortical vesicles was significantly more sensitive to inhibition by phlorizin. These results suggest the existence of two distinct sodium-dependent D-glucose transport systems in the renal proximal tubule brush border membrane. The kinetic studies presented here were done under zero trans sodium and glucose conditions. The rationale and methodology for carrying out these measurements reliably are discussed in detail.

Transport of guanidine in rabbit intestinal brush-border membrane vesicles

1988 ◽  
Vol 255 (1) ◽  
pp. G85-G92 ◽  
Author(s):  
Y. Miyamoto ◽  
V. Ganapathy ◽  
F. H. Leibach
Keyword(s):  
Brush Border ◽  
Time Course ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Extracellular Ph ◽  
Brush Border Membrane Vesicles ◽  
Intestinal Brush Border Membrane ◽  
Intestinal Brush Border ◽  
Dependent Transport ◽  
Proximal Intestine

The characteristics of guanidine uptake were studied in brush-border membrane vesicles isolated from the rabbit proximal intestine. Guanidine uptake was manyfold greater in the presence of an outward-directed H+ gradient (intracellular pH = 5.5; extracellular pH = 7.2) than in the absence of a H+ gradient (intracellular and extracellular pH = 7.2). The time course of guanidine uptake exhibited an overshoot phenomenon in the presence of the H+ gradient, indicating occurrence of uphill transport. This H+ gradient-stimulated guanidine uptake was not due to an inside-negative H+-diffusion potential because carbonyl cyanide 4-trifluoromethoxyphenylhydrazone, a protonophore, failed to have any effect on guanidine uptake. Moreover, the transient uphill transport of guanidine was observed even in voltage-clamped membrane vesicles. However, under the conditions that effectively dissipated the H+ gradient, there was no active transport of guanidine. This H+ gradient-dependent transport mechanism for guanidine is distinct from the Na+-H+ exchanger, because amiloride did not inhibit guanidine uptake even at a concentration as high as 100 microM. These data provide evidence for the presence of a guanidine-H+ antiport system in the rabbit intestinal brush-border membrane. The presence of a carrier for guanidine in these membranes is further substantiated by the trans-stimulation of the uptake of radiolabeled guanidine by unlabeled guanidine and by the inhibition of guanidine uptake by imipramine under equilibrium exchange conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium-pyrazinoate cotransport in rabbit renal brush border membrane vesicles

1985 ◽  
Vol 249 (3) ◽  
pp. F400-F408 ◽  
Author(s):  
M. Manganel ◽  
F. Roch-Ramel ◽  
H. Murer
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Organic Anion ◽  
Membrane Vesicles ◽  
Sodium Concentration ◽  
Brush Border Membrane Vesicles ◽  
Renal Brush Border Membrane ◽  
Sodium Dependent ◽  
Dependent Transport ◽  
Renal Brush Border

Pyrazinoate (PZA) is an organic anion actively reabsorbed and secreted in the mammalian kidney. In experiments with rabbit renal brush border membrane vesicles, we characterized a sodium-PZA cotransport mechanism that could be involved in reabsorption. An inwardly directed sodium gradient stimulated the influx of PZA. The sodium-dependent transport was electroneutral, suggesting a 1:1 stoichiometry. The kinetic constants for sodium-PZA cotransport were measured under initial linear flux and zero trans conditions for both sodium and PZA. The apparent Km for sodium was about 60 mM. At 90 mM sodium the apparent Km for PZA was about 1.1 mM; increasing the sodium concentration augmented the apparent affinity for PZA. Cis inhibition of sodium-dependent PZA uptake was observed by the addition of nicotinate, lactate, probenecid, succinate, beta-hydroxybutyrate, and salicylate. Urate had no effect. [14C]PZA uptake was trans stimulated by PZA itself, lactate, and nicotinate. PZA shares a transport system(s) involved in the proximal tubular reabsorption of these two anions.

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