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.

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.

K-Cl transport systems in rabbit renal basolateral membrane vesicles

1987 ◽  
Vol 252 (5) ◽  
pp. F883-F889 ◽  
Author(s):  
J. Eveloff ◽  
D. G. Warnock
Keyword(s):  
Carboxylic Acid ◽  
Renal Cortex ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Chloride Conductance ◽  
Transport Systems ◽  
Basolateral Membrane Vesicles ◽  
Transport Pathways ◽  
System A ◽  
Potassium Gradient

The transport pathways for chloride in basolateral membrane vesicles from the rabbit renal cortex were investigated. 36Cl uptake was stimulated by the presence of potassium in the uptake media compared with sodium or N-methyl-D-glucamine. In addition, potassium (86Rb) uptake was stimulated more by chloride than by nitrate or gluconate. Neither of these processes was further stimulated by potassium gradients plus valinomycin, suggesting the presence of an electrically neutral K-Cl cotransport system. A magnesium-induced chloride conductance was also found in the basolateral membrane vesicles. In the absence of magnesium, the chloride conductance was low; valinomycin and an inwardly directed potassium gradient did not stimulate 36Cl uptake, anthracene-9-carboxylic acid did not inhibit 36Cl uptake, and valinomycin did not stimulate chloride-dependent 86Rb uptake. However, in the presence of 1 mM magnesium, opposite results were obtained; valinomycin and an inwardly directed potassium gradient stimulated 36Cl uptake, anthracene-9-carboxylic acid inhibited 36Cl uptake, and valinomycin stimulated chloride-dependent 86Rb uptake. Therefore, an electrically neutral K-Cl cotransport and magnesium-induced chloride conductance were found in renal cortical basolateral membrane vesicles prepared from the rabbit renal cortex.

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.

Depression of calcium pump activity in renal cortex of vitamin D-deficient rats with secondary hyperparathyroidism

1990 ◽  
Vol 123 (4) ◽  
pp. 438-444 ◽  
Author(s):  
Yusuke Tsukamoto ◽  
Teiichi Tamura ◽  
Michiyo Saitoh ◽  
Yumiko Takita ◽  
Toshiaki Nakano
Keyword(s):  
Vitamin D ◽  
Secondary Hyperparathyroidism ◽  
Hormonal Regulation ◽  
Serum Calcium Level ◽  
Renal Cortex ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Calcium Pump ◽  
Basolateral Membrane Vesicles ◽  
Pump Activity

Abstract. To examine the hormonal regulation of the ATP-dependent Ca2+ pump in the kidneys, the ATP-dependent Ca2+ uptake by the basolateral membrane vesicles in the renal cortex was measured using radioactive calcium (45Ca2+) in rats with vitamin D deficiency or rats undergoing thyroparathyroidectomy. The Vmax of the Ca2+ pump activity was increased not only by administering calcitriol, but also by normalizing the serum calcium level in vitamin D-deficient rats. PTH suppressed the Ca2+ pump activity in normocalcemic vitamin D-deficient rats. Thyroparathyroidectomy did not affect the Ca2+ pump activity in the kidneys of normal rats. It was concluded that the ATP-dependent Ca2+ pump activity was depressed by secondary hyperparathyroidism in vitamin D-deficient rats.

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.

Comparative analysis of ontogenic changes in renal and intestinal biotin transport in the rat

2003 ◽  
Vol 284 (4) ◽  
pp. F737-F742 ◽  
Author(s):  
Svetlana M. Nabokina ◽  
Veedamali S. Subramanian ◽  
Hamid M. Said
Keyword(s):  
Age Groups ◽  
Membrane Vesicles ◽  
Transport Processes ◽  
Water Soluble ◽  
Kidney Cortex ◽  
Intestinal Epithelial ◽  
Adult Rats ◽  
Intestinal Epithelia ◽  
Sodium Dependent ◽  
Uptake Process

Biotin, an essential water-soluble micronutrient, cannot be synthesized by mammals; rather, it is obtained from exogenous sources via uptake by intestinal epithelia. Renal epithelia reclaim the vitamin that is filtered in the glomeruli. Both epithelia take up biotin via the sodium-dependent multivitamin transporter (SMVT). Little is known about ontogenic regulation of the renal and intestinal biotin transport processes and about the mechanism(s) involved in any such regulation. In this study, we sought to examine and compare ontogenic aspects of the renal and intestinal biotin uptake processes using purified brush-border membrane vesicles (BBMV) isolated from the kidney cortex and jejunum of suckling and adult rats. Clear ontogenic changes were observed in the intestinal biotin uptake process, which were mediated via changes in V max and apparent K m. Parallel changes were also seen in protein, mRNA, and transcription rate of SMVT as indicated by results of Western blotting, RT-PCR, and nuclear run-on assays, respectively. In contrast, biotin uptake by renal BBMV did not show ontogenic changes; i.e., it was similar in suckling and adult rats. Also, the levels of SMVT protein and mRNA were similar in the kidneys of both age groups. These data show that biotin uptake by renal and intestinal epithelial cells responds differently to ontogenic regulation. In addition, the ontogenic changes observed in the intestinal biotin uptake process involve the entry step of the vitamin at the BBM and appear to be mediated via a transcriptional mechanism(s).

A D-mannose transport system in renal brush-border membranes

1989 ◽  
Vol 257 (6) ◽  
pp. F1100-F1107 ◽  
Author(s):  
D. C. Mendelssohn ◽  
M. Silverman
Keyword(s):  
Brush Border ◽  
High Capacity ◽  
Membrane Vesicles ◽  
Hydroxyl Group ◽  
Kidney Cortex ◽  
Equatorial Orientation ◽  
High Concentration ◽  
Renal Brush Border Membrane ◽  
Sodium Dependent ◽  
Renal Brush Border

Dog renal brush-border membrane vesicles (BBMV) from whole kidney cortex contain both low-affinity, high-capacity and high-affinity, low-capacity Na-dependent D-glucose cotransporters. D-Mannose is an epimer of D-glucose, differing in structure only in the axial, rather than equatorial, orientation of the hydroxyl group at the C-2 position of the pyranose ring. Uptake experiments of radioactive sugars into BBMV by standard Millipore filtration were performed to determine whether D-mannose shares either, or both, of the D-glucose carriers or if it is transported by an independent system. Transport of D-mannose occurs into an osmotically active space and is saturable and sodium dependent with a 1:1 Na:D-mannose stoichiometry, Km of 0.063 mM, Vmax of 3.6 nmol.mg-1.min-1, 25 degrees C, and pH 7.4. When an NaSCN electrochemical gradient was present, an “overshoot” was present, indicating active cotransport. Up to 50 mM D-mannose did not inhibit sodium-dependent D-glucose or alpha-methylglucoside uptake (0.01–20 mM). Sodium-dependent D-mannose uptake was inhibited by the following compounds in order of decreasing effectiveness: fructose greater than mannoheptulose greater than 2-deoxy-D-glucose greater than 2-fluoro-2-deoxy-D-glucose much greater than phloretin, cytochalasin B, galactose, 3-O-methyl-D-glucose, and L-mannose. Phlorizin also inhibited D-mannose uptake, but the high concentration required and the fact that a competitive pattern of inhibition could not be demonstrated contrasted with its effect on D-glucose transport.(ABSTRACT TRUNCATED AT 250 WORDS)

Is leucine an allosteric modulator of the lysine transporter in the intestinal basolateral membrane?

1987 ◽  
Vol 253 (5) ◽  
pp. G637-G642 ◽  
Author(s):  
K. Lawless ◽  
D. Maenz ◽  
C. Cheeseman
Keyword(s):  
Amino Acid ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Low Concentrations ◽  
Carrier Mediated Transport ◽  
Order Of Magnitude ◽  
Dibasic Amino Acid ◽  
Voltage Clamping ◽  
Stimulation Of

The transport of the dibasic amino acid L-lysine was investigated using basolateral membrane vesicles prepared from rat jejunal mucosal scrapings. The majority of the carrier-mediated transport was unaffected by the presence of sodium in the incubation medium, but voltage clamping of the vesicles did increase lysine uptake, indicating an associated movement of charge. Kinetic analysis of lysine influx and efflux showed the system to be symmetrical, but although the Vmax was comparable to other amino acid transport systems in this membrane, the dissociation constant for the overall reaction (KT) was an order of magnitude larger. This low affinity for lysine would explain the relatively slow rate of transport of this amino acid across the basolateral membrane. Competition experiments indicated that this system has a relatively narrow specificity carrying only lysine, arginine, ornithine, and histidine. In contrast the presence of L-leucine caused a marked stimulation of lysine efflux and influx across the vesicles. This effect was observed with leucine concentrations as low as 0.1 microM. It is concluded that although the lysine transport system in the basolateral membrane is slow in its basal state it can be rapidly turned on by the presence of L-leucine. The remarkably low concentrations required to do this suggest a possible allosteric interaction between the transporter and this neutral amino acid.

Sign in / Sign up

Export Citation Format

Share Document