Free cadmium activity in renal epithelial cells is enhanced by Mg2+ depletion.
Free Cd2+ uptake was determined by fluorescence techniques with the use of mag-fura-2 in single epithelial MDCK cells. Cytosolic Cd2+ increased in a time-dependent and concentration-dependent manner following the addition of cadmium to the external solution. The increment in cytosolic Cd2+ was greater in magnesium-depleted cells relative to normal cells. Uptake in normal and magnesium-depleted cells was inhibited by the channel antagonist, verapamil, and increased with the agonist, Bay K 8644. These studies indicate that free Cd2+ may exist in the cell cytosol and Cd2+ uptake is greater following magnesium-depletion. These data support the notion that magnesium may provide a cytoprotective effect in cadmium toxicity.
Quamme
G A
GA
Department of Medicine, University of British Columbia, University Hospital, Vancouver, Canada.
D000818:Animals; D001693:Biological Transport, Active; D002104:Cadmium / Q000493:pharmacokinetics* / Q000633:toxicity; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004848:Epithelium / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D002104:Cadmium; C049925:fura-2-am; D008274:Magnesium; D002118:Calcium; D016257:Fura-2