scholarly journals Effect of acidosis on glutamine transport by isolated rat renal brush-border and basolateral-membrane vesicles

1983 ◽  
Vol 212 (3) ◽  
pp. 713-720 ◽  
Author(s):  
J W Foreman ◽  
R A Reynolds ◽  
K Ginkinger ◽  
S Segal
Keyword(s):  
Brush Border ◽  
Initial Rate ◽  
Basolateral Membrane ◽  
High Capacity ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Basolateral Membrane Vesicles ◽  
Glutamine Transport ◽  
Glutamine Uptake ◽  
Renal Brush Border

Glutamine uptake was examined in isolated renal brush-border and basolateral-membrane vesicles from control and acidotic rats. In brush-border vesicles from acidotic animals, there was a significant increase in the initial rate of glutamine uptake compared with that in controls. Lowering the pH of the medium increased the initial rate of glutamine uptake in brush-border vesicles from acidotic, but not from control, rats. In brush-border vesicles from both groups of animals, two saturable transport systems mediated glutamine uptake. There was a 2-fold increase in the Vmax. of the low-affinity high-capacity system in the brush-border vesicles from the acidotic animals compared with that from control animals, with no alteration in the other kinetic parameters. There was no difference in glutamine uptake by the two saturable transport systems in basolateral vesicles from control and acidotic animals. Lowering the incubation-medium pH increased the uptake of glutamine by basolateral vesicles from both control and acidotic rats to a similar extent. The data indicate that during acidosis there are alterations in glutamine transport by both the basolateral and brush-border membrane which could enhance its uptake by the renal-tubule cell for use in ammoniagenesis.

scholarly journals Characterization of sodium-dependent and sodium-independent nucleoside transport systems in rabbit brush-border and basolateral plasma-membrane vesicles from the renal outer cortex

1989 ◽  
Vol 264 (1) ◽  
pp. 223-231 ◽  
Author(s):  
T C Williams ◽  
A J Doherty ◽  
D A Griffith ◽  
S M Jarvis
Keyword(s):  
Brush Border ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Nucleoside Transport ◽  
Transport Systems ◽  
Facilitated Diffusion ◽  
Basolateral Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Outer Cortex ◽  
Overshoot Phenomenon

The transport of uridine into rabbit renal outer-cortical brush-border and basolateral membrane vesicles was compared at 22 degrees C. Uridine was taken up into an osmotically active space in the absence of metabolism for both types of membrane vesicles. Uridine influx by brush-border membrane vesicles was stimulated by Na+, and in the presence of inwardly directed gradients of Na+ a transient overshoot phenomenon was observed, indicating active transport. Kinetic analysis of the saturable Na+-dependent component of uridine flux indicated that it was consistent with Michaelis-Menten kinetics (Km 12 +/- 3 microM, Vmax. 3.9 +/- 0.9 pmol/s per mg of protein). The sodium:uridine coupling stoichiometry was found to be consistent with 1:1 and involved the net transfer of positive charge. In contrast, uridine influx by basolateral membrane vesicles was not dependent on the cation present and was inhibited by nitrobenzylthioinosine (NBMPR). NBMPR-sensitive uridine transport was saturable (Km 137 +/- 20 microM, Vmax. 5.2 +/- 0.6 pmol/s per mg of protein). Inhibition of uridine flux by NBMPR was associated with high-affinity binding of NBMPR to the basolateral membrane (Kd 0.74 +/- 0.46 nM). Binding of NBMPR to these sites was competitively blocked by adenosine and uridine. These results indicate that uridine crosses the brush-border surface of rabbit proximal renal tubule cells by Na+-dependent pathways, but permeates the basolateral surface by NBMPR-sensitive facilitated-diffusion carriers.

Glutamine transport in renal basolateral vesicles from dogs with metabolic acidosis

1984 ◽  
Vol 246 (1) ◽  
pp. F78-F86 ◽  
Author(s):  
D. W. Windus ◽  
D. E. Cohn ◽  
S. Klahr ◽  
M. R. Hammerman
Keyword(s):  
Metabolic Acidosis ◽  
Initial Rate ◽  
Basolateral Membrane ◽  
Cortical Cell ◽  
Membrane Vesicles ◽  
Ammonia Production ◽  
Basolateral Membrane Vesicles ◽  
Electrogenic Transport ◽  
Chronic Metabolic Acidosis ◽  
Glutamine Transport

To determine whether the increased ammonia production per nephron in chronic metabolic acidosis is accompanied by augmented L-glutamine transport across the basolateral membrane of the renal cortical cell and consequent increased availability of this ammoniagenic amino acid, we measured L-[3H]glutamine transport in basolateral membrane vesicles (BLMV) isolated from kidneys of normal and acidotic dogs. Na+ -dependent electrogenic transport of L-[3H]glutamine was demonstrated in BLMV from kidneys of normal dogs that exhibited saturability over the concentration range of 25 microM to 2 mM L-glutamine. The apparent Km was 416 +/- 114 microM and Vmax was 536 +/- 129 pmol X mg protein-1 X 15 s-1. The initial rate of Na+ -dependent L-[3H]glutamine transport was increased in BLMV from kidneys of acidotic dogs, as reflected by an increased apparent Vmax. We conclude that an adaptation resulting in greater uptake of L-glutamine across the basolateral membrane of the renal cortical cell may underlie, in part, the increased rate of ammonia production per nephron seen in chronic metabolic acidosis.

Glutamine uptake by rat renal basolateral membrane vesicles

1982 ◽  
Vol 2 (11) ◽  
pp. 883-890 ◽  
Author(s):  
Robert A. Reynolds ◽  
Hanna Wald ◽  
Stanton Segal
Keyword(s):  
Renal Cortex ◽  
Basolateral Membrane ◽  
High Capacity ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Glutamine Concentration ◽  
Sodium Dependent ◽  
Uptake Process ◽  
Dibasic Amino Acids ◽  
Glutamine Uptake

The presence of a sodium-dependent, saturable uptake process is described in basolateral membranes of rat renal cortex for L-glutamine. Concentration-dependence studies indicate the presence of multiple transport systems with Km1 of 0.032 mM and V1 of 0.028 nmol/mg of protein per min, and Km2 of 17.6 mM and V2 of 17.6 nmol/mg of protein per min. Lysine completely inhibits the high-affinity, low-capacity Km system and partially inhibits the low-affinity, high-capacity system. Cystine and other dibasic amino acids also affect glutamine uptake.

Sensitivity of rat renal luminal and contraluminal sulfate transport systems to DIDS

1986 ◽  
Vol 250 (2) ◽  
pp. F226-F234 ◽  
Author(s):  
C. Bastlein ◽  
G. Burckhardt
Keyword(s):  
Transport System ◽  
Brush Border ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Basolateral Membrane Vesicles ◽  
Sulfate Transport ◽  
Sulfate Uptake ◽  
Basolateral Membranes ◽  
Irreversible Inhibition

4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) was tested as an inhibitor of the sulfate transport systems in rat renal brush border and basolateral membrane vesicles. Na+-driven sulfate uptake into brush border membrane vesicles was half-maximally inhibited at 350 microM DIDS. Proton gradient-driven sulfate uptake into basolateral membrane vesicles was competitively inhibited by DIDS with a Ki of 2.4 microM. The Km for delta pH-driven sulfate uptake was 5.4 microM. The different affinities of the sulfate transport systems for DIDS correlated with different substrate specificities. The luminal transport system accepted a smaller range of anions than the contraluminal system and did not operate as a Na+-independent anion exchanger. After treatment of basolateral membrane vesicles with 50 microM DIDS at pH 8.4 for 30 min, an irreversible inhibition of sulfate uptake was observed. With brush border membranes, only a small irreversible inhibition was obtained. Lack of inhibition after treatment of basolateral membranes with DIDS at pH 6.4 indicated that DIDS reacted with deprotonated amino groups of the transport protein. Sulfate was protected from the irreversible inhibition by DIDS. Sodium-driven uptake of L-glutamate and methylsuccinate into basolateral membrane vesicles was not irreversibly inhibited by DIDS, indicating a specific action of DIDS on the contraluminal sulfate transport system. Irreversible and substrate-protectable inhibition of sulfate transport render DIDS suitable for future affinity labeling studies on the sulfate transport system in basolateral membranes.

Effect of Lamivudine on Uptake of Organic Cations by Rat Renal Brush-Border and Basolateral Membrane Vesicles

2000 ◽  
Vol 52 (5) ◽  
pp. 569-575 ◽  
Author(s):  
TAKATOSHI TAKUBO ◽  
TOSHIHIRO KATO ◽  
JUNJI KINAMI ◽  
KAZUHIKO HANADA ◽  
HIROYASU OGATA
Keyword(s):  
Brush Border ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Organic Cations ◽  
Basolateral Membrane Vesicles ◽  
Renal Brush Border
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