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Madin-Darby canine kidney cells (1990)

Oberleithner, H. ; Vogel, U. ; Kersting, U. ; [et al.]

Springer

Pflügers Archiv 416 (1990), S. 533-539

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ISSN: 1432-2013

Keywords: MDCK-cells ; Aldosterone ; Na+/H+ exchange ; Cl−/HCO 3 − exchange ; Intercalated cells

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract Experiments in dome epithelium of Madin-Darby canine kidney (MDCK) cells were performed to elucidate aldosterone action on acid-base transport. By means of pH-sensitive microelectrodes the pH of the dome fluid was measured while the apical plasma membrane was superfused. In the absence of HCO 3 − the dome fluid (facing the basolateral cell membrane) alkalinized in response to 10−7 mol/l aldosterone. Amiloride (10−3 mol/l) inhibited dome formation and pH recovery of the dome fluid from an extracellular acid load. In the presence of HCO 3 − dome fluid acidified in response to aldosterone. The stilbene derivative diisothiocyanate-stilbene-2,2′-disulphonic acid (DIDS) or removal of Cl− from the apical perfusate inhibited this dome acidification. In aldosterone-depleted MDCK monolayers HCO 3 − was actively accumulated in the dome fluid in contrast to aldosterone-supplemented cells. The results indicate that aldosterone stimulates both amiloride-sensitive Na+/H+ exchange and DIDS-sensitive Cl−/HCO 3 − exchange in the apical cell membrane of MDCK cells. In the absence of aldosterone the HCO 3 − extrusion process is localized in the basolateral membrane in series with apical Na+/H+ exchange, while in the presence of aldosterone Cl−/HCO 3 − is mainly localized in the apical membrane in parallel with Na+/H+ exchange. Cl− exits the cell through apical Cl− channels and is absorbed via the paracellular route.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00382686

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Phenotypically and karyotypically distinct Madin-Darby canine kidney cell clones respond differently to alkaline stress (1995)

Wünsch, S. ; Gekle, M. ; Kersting, U. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 164 (1995), S. 164-171

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: We isolated two cell clones from the wild-type Madin-Darby canine kidney cell line (MDCK) that resembles renal collecting duct epithelium. Morphology and karyotypes of the two cell clones were evaluated. The MDCK-C7 cell clone morphologically resembles principal cells (polygonal cell shape, flat), while the MDCK-C11 clone resembles intercalated cells (cuboidal cell shape, high). The diploid chromosome number of MDCK-C7 cells is 83.1 ± 0.2 (n = 139); that for MDCK-C11 cells is 78.8 ± 0.1 (n = 128). Culture of MDCK-C7 cells in alkaline medium (pH 7.7) induced irreversible phenotypical and genotypical alterations. transformed MDCK-C7F cells are characterized by two abnormal (biarmed) chromosomes. In contrast, MDCK-C11 cells are not phenotypically altered by alkaline stress. In order to elucidate the role of intracellular pH (pHi) in the transformation process, we measured pHi under control conditions (pH 7.4). after 5 min exposure to alkaline stress (“acute experiment,” pH 7.7) and after incubation of the cells in alkaline medium for two weeks (“chronic experiment,” pH 7.7). Under control conditions, MDCK-C7 cells maintained pHi at 7.14 ± 0.01 (n = 154) and MDCK-C11 cells at 7.01 ± 0.01 (n = 147). Acute alkaline stress increased pHi of both cell types to similar steady-state values. Under chronic alkaline stress, MDCK-C7 cells were unable to maintain intracellular pH within normal limits exhibiting sustained alkalinization, whereas MDCK-C11 cells could successfully regulate pHi. We conclude that wild-type MDCK cells consist of two genetically distinct subpopulations with different morphology and function. Only the MDCK-C7 clone that resembles the principle cell type of renal collecting duct can be transformed by alkaline stress while the MDCK-C11 clone resists this treatment, due to efficient pHi control mechanisms. © 1995 Wiley-Liss, Inc.

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