Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.2.1.7 (BAL)
 1,977 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effects of pH on internalization, membrane-binding and efflux of Cd were investigated in LLC-PK1 cells and these effects were compared with those of inorganic mercury (Hg). The cells cultured on monolayers were incubated for 30 min in phosphate buffer at pH 5.5, 6.4 or 7.4 containing 1 microM Cd or Hg. After the incubation, the cells were washed with phosphate buffered saline (PBS) or PBS containing chelating agent (EGTA or BAL) to remove membrane-bound Cd or Hg. The decrease in pH significantly decreased Cd concentration in the cells washed with PBS and with PBS-EGTA, and apparently increased the efflux of Cd from the cells. Similar changes were found in Hg concentration in the cells washed with PBS-BAL and Hg efflux from the cells, but these changes in Hg were less significant than those in Cd, respectively. The decrease in pH-increased Hg concentration in the cells washed with PBS, unlike that of Cd. These results suggest that a decrease in pH decreases the internalized Cd as a result of the decrease in membrane-bound Cd and the increase in Cd efflux. The decrease in pH also appears to decrease the internalized Hg by increasing Hg efflux and to increase the membrane-bound Hg.
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PMID:Comparative studies of cadmium and mercury accumulation by LLC-PK1 cells: effects of pH on uptake and efflux. 891 14

The purpose of this study was to investigate the mechanism of inorganic mercury (Hg) uptake in LLC-PK1 cells, a renal tubular epithelial cell line, and to compare the results with those reported previously by us in rat renal cortical epithelial (RCE) cells in primary culture. The LLC-PK1 cells were cultured for 3-12 days, incubated with 1 microM HgCl2 in Hanks' balanced salt solution at 4 or 37 degrees C for 30 min, and washed with phosphate-buffered saline containing BAL to remove the cell membrane-bound Hg. The uptake of Hg was higher in nonconfluent cultures than in confluent cultures and higher at 37 than at 4 degrees C. In confluent culture (Day 8) Hg uptake at 4 degrees C was only 27% of that at 37 degrees C. The initial accumulation of Hg (5 min) from different concentrations of HgCl2 (0.5-50 microM) was linear and did not show a tendency toward saturation, suggesting that a carrier-mediated process was not involved. Pretreatment of cells with 10 microM FCCP, a metabolic inhibitor and a proton ionophore, 0.5 mm DIDS, an anion transport inhibitor, or 0.5 mM ouabain, a Na+/K+-ATPase inhibitor, resulted in 72, 60, and 57% reduction in Hg uptake, respectively. Furthermore, replacement of 137 mm NaCl in the incubation medium with 137 mM KCl or LiCl or 274 mM mannitol caused 30, 45, and 87% reduction in Hg uptake, respectively. These results suggest that in LLC-PK1 cells, as in RCE cells, Hg uptake is inversely related to cell density and is influenced by membrane fluidity, membrane potential, and HCO3-/Cl- transporter.
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PMID:Mercury uptake by LLC-PK1 cells: dependence on temperature and membrane potential. 934 97