Sodium-dependent phosphate transport by apical membrane vesicles from a cultured renal epithelial cell line (LLC-PK1)

1984 ◽  
Vol 769 (2) ◽  
pp. 471-478 ◽  
Author(s):  
C.D.A. Brown ◽  
M. Bodmer ◽  
J. Biber ◽  
H. Murer
Keyword(s):  
Epithelial Cell ◽  
Cell Line ◽  
Apical Membrane ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Sodium Dependent ◽  
Renal Epithelial Cell Line ◽  
Apical Membrane Vesicles

Na+-dependent hexose transport in vesicles from cultured renal epithelial cell line

1982 ◽  
Vol 243 (5) ◽  
pp. C293-C298 ◽  
Author(s):  
A. Moran ◽  
J. S. Handler ◽  
R. J. Turner
Keyword(s):  
Apical Membrane ◽  
Membrane Vesicles ◽  
Sodium Concentration ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Vesicle Preparation ◽  
Dependent Component ◽  
Sodium Dependent ◽  
Renal Epithelial Cell Line ◽  
Apical Membrane Vesicles

Apical membrane vesicles were prepared from cultured epithelia formed by LLC-PK1 cells using a calcium precipitation technique. alpha-Methylglucoside uptake into this vesicle preparation was markedly stimulated by sodium and inhibited by phlorizin. In addition, a transient "overshoot" of intravesicular alpha-methylglucoside concentration above its equilibrium value was observed under initial sodium gradient conditions. The specificity of this sodium-dependent hexose transporter closely resembled that found in the mammalian kidney brush border membrane, e.g., alpha-methylglucoside, D-glucose, and D-galactose apparently share the transporter while 2-deoxy-D-glucose, mannose, and fructose do not. Kinetic analysis of the sodium-dependent component of alpha-methylglucoside flux into LLC-PK1 apical membrane vesicles indicates the existence of single transporter with Km congruent to 2 mM and Vmax congruent to 3 nmol.min-1.mg protein-1. Measurement of alpha-methylglucoside uptake as a function of sodium concentration is consistent with a sodium:sugar stoichiometry of approximately 2:1.l There is a good correlation over time between the development of the concentrating capacity of the intact epithelium for alpha-methylglucoside and the transport properties of the vesicle preparation.

scholarly journals H+-gradient-dependent active transport of tetraethylammonium cation in apical-membrane vesicles isolated from kidney epithelial cell line LLC-PK1

1985 ◽  
Vol 227 (1) ◽  
pp. 199-203 ◽  
Author(s):  
K Inui ◽  
H Saito ◽  
R Hori
Keyword(s):  
Epithelial Cell ◽  
Cell Line ◽  
Apical Membrane ◽  
Membrane Vesicles ◽  
Epithelial Cell Line ◽  
Overshoot Phenomenon ◽  
Kidney Epithelial Cell ◽  
Kidney Epithelial Cell Line ◽  
Apical Membranes ◽  
Apical Membrane Vesicles

Transport of [3H]tetraethylammonium (NEt4+), an organic cation, has been studied by using apical-membrane vesicles isolated from cultured kidney epithelial cell line LLC-PK1. The uptake of NEt4+ by apical-membrane vesicles was osmotically sensitive, time-dependent and saturable. The presence of an H+ gradient ([H+]i greater than [H+]o) induced a marked stimulation of NEt4+ uptake against its concentration gradient (overshoot phenomenon), and this concentrative uptake was inhibited by HgCl2. These results suggest that apical membranes isolated from the LLC-PK1 cells retain the transport characteristics of NEt4+ similar to those observed in renal brush-border membranes.

Electrophysiological Measurements of a Toad Renal Epithelial Cell Line (A6) as an Assay for Predicting Ocular Eye Irritancy

1992 ◽  
Vol 20 (2) ◽  
pp. 218-221
Author(s):  
Henning F. Bjerregaard
Keyword(s):  
Epithelial Cell ◽  
Cell Line ◽  
South African ◽  
Mdck Cells ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Electrophysiological Measurements ◽  
Renal Epithelial Cell Line ◽  
Darby Canine Kidney

An established epithelial cell line (A6) from a South African clawed toad (Xenopus laevis) kidney was used as a model for the corneal epithelium of the eye in order to determine ocular irritancy. When grown on Millipore filter inserts, A6 cells form a monolayer epithelium of high electrical resistance and generate a trans-epithelial potential difference. These two easily-measured electrophysiological endpoints showed a dose-related decrease after exposure for 24 hours to seven selected chemicals of different ocular irritancy potential. It was demonstrated that both trans-epithelial resistance and potential ranked closely with in vivo eye irritancy data and correlated well (r = 0.96) with loss of trans-epithelial impermeability of Madin-Darby canine kidney (MDCK) cells, detected by use of a fluorescein leakage assay.

scholarly journals Expression of phosphoenolpyruvate carboxykinase (PEPCK) chimeras in renal epithelial cells. Retention of appropriate physiological responsiveness using enhancerless retroviral vectors

1992 ◽  
Vol 284 (3) ◽  
pp. 725-732 ◽  
Author(s):  
A S Pollock ◽  
D H Lovett
Keyword(s):  
Epithelial Cell ◽  
Cyclic Amp ◽  
Cell Line ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Large Fraction ◽  
Expression System ◽  
Retroviral Vectors ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Renal Epithelial Cell Line

We used an enhancerless U3 mutant retroviral vector to deliver chimeras of the phosphoenolpyruvate carboxykinase (PEPCK) promoter region to a renal epithelial cell line capable of expressing PEPCK mRNA. Chimeras consisting of the PEPCK promoter and chloramphenicol acetyltransferase, neomycin phosphotransferase or human growth hormone genes were expressed after viral infection of the NRK52E renal epithelial cell line. Virus-delivered sequences in which the direction of PEPCK promoter transcription was antegrade to the normal direction of the long terminal repeat (LTR)-initiated transcription correctly upon stimulation with dexamethasone or 8-bromo cyclic AMP and upon lowering of the extracellular pH. Fluorescent primer extension in situ using primers specific for virus-delivered sequences of antegrade constructs indicated that a large fraction of NRK52E cells could be infected by co-cultivation with virus-producing psi-2 cells without G418 selection. Virus-delivered constructs whose orientation was opposite to that of the LTRs were expressed at very low levels, with transcripts detectable by PCR only in RNA from cyclic AMP-treated cells. Using reverse transcription/PCR, we demonstrated that the chimeric transcripts were from the internal PEPCK promoter rather than a functional or reconstituted Moloney LTR. PEPCK-reporter chimeras delivered by retroviral vectors demonstrated a level of expression more consistent with the level of expression of the native PEPCK gene than did transfected chimeras. This expression system should prove useful for studies of the physiological modulation of gene expression in renal tissues.

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