Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used three fluorescent probes to label acid-base transporting cells with specific physiological properties in the rabbit collecting duct. Rhodamine albumin identified cells active in luminal endocytosis; rhodamine peanut agglutinin (PNA) identified cells with apical surface PNA ligands; and 6-carboxyfluorescein (6-CF) diacetate identified cells with alkaline pH or acetazolamide-sensitive esterase activity. More than 90% of all cells identified by PNA or rhodamine albumin selectively concentrated 6-CF. Axial heterogeneity of the identified cells was clearly evident along the collecting duct. In the midcortical collecting duct the predominant labeled cell (108 +/- 15/mm) was positive for PNA and 6-CF. These cells were less prevalent (69 +/- 10/mm) in inner cortical collecting ducts and absent from the outer medullary collecting duct. Cells that labeled only with 6-CF (with no detectable luminal endocytosis or PNA binding) showed the opposite distribution. They were the predominant identified cell in the inner stripe of the outer medulla (126 +/- 20/mm), and were less common in the cortical collecting duct. Because the former segment secretes H+, it was likely that these cells were H+-secreting cells. We used excitation ratio microspectrofluorometry of 6-CF to measure cytosolic pH (pHi approximately 7.2) and found evidence for a basolateral DIDS-sensitive Cl- -HCO3- exchanger and a Na+-independent luminal H+ pump. The previously described endocytic H+-secreting cell was seen at its highest concentration in the outer stripe (39 +/- 6/mm). Finally, 5-10% of identified cells did not stain selectively with 6-CF in cortical collecting ducts (solely endocytic or PNA binding). The function of these latter types could not be established. These studies suggest that the distribution and number of these populations of cells may determine the direction and magnitude of H+ transport along the collecting duct.
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PMID:Fluorescent characterization of collecting duct cells: a second H+-secreting type. 246 Oct 95

Cadmium toxicity to renal cells was investigated in Madin-Darby canine kidney (MDCK) and LLC-PK1 cells as models of the distal tubule/collecting duct and proximal tubule, respectively. Cells were grown on two-compartment filters and exposed to 0.1-50 microM Cd2+. In MDCK cells, Cd2+ was more toxic from the basolateral than from the apical side and dependent on the extracellular Ca2+ concentration. Toxicity was evident within 24 h, as shown by a decrease in transepithelial resistance (TER), reduced proliferation (bromodeoxyuridine incorporation), reduction in ATP concentration, and morphological changes. On confocal microscopy, E-cadherin and alpha-catenin staining patterns indicated interference with the cadherin-catenin complex. LLC-PK1 cells showed a similar toxicity pattern, which was evident at lower Cd2+ concentrations. An increase of E-cadherin and alpha-catenin molecules in the Triton X-100-insoluble fraction was detectable at high Cd2+ concentrations in LLC-PK1 cells but not in MDCK cells. Lactate dehydrogenase release indicated membrane leakage in LLC-PK1 cells. Rhodamine-phalloidin staining, a probe for F-actin filaments, demonstrated alterations of the actin cytoskeleton in both cell lines. In conclusion, cadmium caused ATP depletion and interfered with the cadherin-catenin complex and probably the tight junctions changing renal cell morphology and function.
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PMID:Cadmium is more toxic to LLC-PK1 cells than to MDCK cells acting on the cadherin-catenin complex. 968 16