Calu-3 cells grown under AIC and LCC conditions: Implications for dipeptide uptake and transepithelial transport of substances

2011 ◽  
Vol 78 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Anna Stentebjerg-Andersen ◽  
Ingrid Vedsted Notlevsen ◽  
Birger Brodin ◽  
Carsten Uhd Nielsen
Keyword(s):  
Transepithelial Transport ◽  
Dipeptide Uptake

Nephrotoxicity Testing In Vitro: The Current Situation

1997 ◽  
Vol 25 (5) ◽  
pp. 497-503
Author(s):  
Jean-Paul Morin ◽  
Marc E. De Broe ◽  
Walter Pfaller ◽  
Gabriele Schmuck
Keyword(s):  
Proximal Tubule ◽  
Culture Media ◽  
Task Force ◽  
Primary Cultures ◽  
Phenotypic Expression ◽  
Transepithelial Transport ◽  
Specific Cell ◽  
Proximal Tubule Cells ◽  
Tubule Cells

An ECVAM task force on nephrotoxicity has been established to advise, in particular, on the follow-up to recommendations made in the ECVAM workshop report on nephrotoxicity testing in vitro. Since this workshop was held, in 1994, there have been several improvements in the techniques used. For example, the duration of renal slice viability, and the maintenance of functional activities in slices, have been improved by using dynamic incubation systems with higher oxygen tensions and more-appropriate cell culture media. Highly differentiated primary cultures of pig, human and rabbit proximal tubule cells have been established by using specific cell isolation procedures and/or selective culture media. To date, the most comparable phenotypic expression and transepithelial transport capacities to proximal tubules in vivo have been obtained with primary cultures of rabbit proximal tubule cells which are grown on bicompartmental supports; in this system, transepithelial substrate gradients are generated and the transepithelial transport of both organic anions and cations is highly active. This in vitro system has been selected by ECVAM for further evaluation and prevalidation. Industrial needs in the area of nephrotoxicity testing have been identified, and recommendations are made at the end of this report concerning possible future initiatives.

Intestinal glycyl-L-phenylalanine and L-phenylalanine transport in a euryhaline teleost

1991 ◽  
Vol 260 (3) ◽  
pp. R563-R569 ◽  
Author(s):  
S. J. Reshkin ◽  
G. A. Ahearn
Keyword(s):  
Significant Contribution ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Transport Mechanisms ◽  
Intestinal Brush Border Membrane ◽  
Overshoot Phenomenon ◽  
Independent Process ◽  
Euryhaline Teleost ◽  
Dipeptide Uptake ◽  
Phenylalanine Transport

The transport mechanisms for the dipeptide glycyl-L-phenylalanine (Gly-Phe) and L-phenylalanine (Phe) were characterized in fish intestinal brush-border membrane vesicles (BBMV). Gly-Phe was rapidly hydrolyzed only intravesicularly with almost total hydrolysis occurring even at 10 s. Dipeptide uptake was not stimulated by an inward gradient of Na, K, or H. Phe uptake was stimulated by an inward gradient of either Na or K but displayed an overshoot phenomenon only in the presence of an Na gradient. Kinetic analysis of the effect of substrate concentration on transport rate revealed that transport of both Gly-Phe and Phe occurred by a saturable process conforming to Michaelis-Menten kinetics. The Km for Gly-Phe was 9.8 +/- 3.5 mM, whereas that for Phe in the presence of Na or K, respectively, was 0.74 +/- 0.13 and 1.1 +/- 0.37 mM. Maximum uptake for Gly-Phe and for Phe in the presence of Na and K was 5.1, 0.9, and 0.4 nmol.mg and protein-1.5 s-1, respectively. Gly-Phe and Phe transport displayed different patterns of inhibition by dipeptides and amino acids. These results suggest that Gly-Phe and Phe are transported via different mechanisms, with Gly-Phe being hydrolyzed during a carrier-mediated, cation-independent process and Phe being transferred via a Na+ cotransport process similar to that described in mammals. During conditions of high luminal dipeptide concentrations, the Gly-Phe pathway may make a significant contribution to total Phe uptake.

Copper repletion enhances apical iron uptake and transepithelial iron transport by Caco-2 cells

2002 ◽  
Vol 282 (3) ◽  
pp. G527-G533 ◽  
Author(s):  
Okhee Han ◽  
Marianne Wessling-Resnick
Keyword(s):  
Iron Uptake ◽  
Iron Transport ◽  
Cell Monolayer ◽  
Transepithelial Transport ◽  
Apical Surface ◽  
Divalent Metal Transporter 1 ◽  
Divalent Metal Transporter ◽  
Metal Transporter ◽  
Copper Status ◽  
Copper Supplementation

The influence of copper status on Caco-2 cell apical iron uptake and transepithelial transport was examined. Cells grown for 7–8 days in media supplemented with 1 μM CuCl2had 10-fold higher cellular levels of copper compared with control. Copper supplementation did not affect the integrity of differentiated Caco-2 cell monolayers grown on microporous membranes. Copper-repleted cells displayed increased uptake of iron as well as increased transport of iron across the cell monolayer. Northern blot analysis revealed that expression of the apical iron transporter divalent metal transporter-1 (DMT1), the basolateral transporter ferroportin-1 (Fpn1), and the putative ferroxidase hephaestin (Heph) was upregulated by copper supplementation, whereas the recently identified ferrireductase duodenal cytochrome b (Dcytb) was not. These results suggest that DMT1, Fpn1, and Heph are involved in the iron uptake process modulated by copper status. Although a clear role for Dcytb was not identified, an apical surface ferrireductase was modulated by copper status, suggesting that its function also contributes to the enhanced iron uptake by copper-repleted cells. A model is proposed wherein copper promotes iron depletion of intestinal Caco-2 cells, creating a deficiency state that induces upregulation of iron transport factors.

Cellular lithium and transepithelial transport across toad urinary bladder

1982 ◽  
Vol 70 (1) ◽  
pp. 69-88 ◽  
Author(s):  
Pauline M. Hughes ◽  
Anthony D. C. Macknight
Keyword(s):  
Urinary Bladder ◽  
Transepithelial Transport ◽  
Toad Urinary Bladder
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