Characterization of furosemide-sensitive Mg2+ influx in Yoshida ascites tumor cells.
Partially Mg2+-depleted Yoshida ascites tumor cells took up Mg2+ after reincubation in Mg2+- and HCO3(-)-containing media. Mg2+ influx was insensitive to ouabain, amiloride and disulfonic stilbenes, but was noncompetitively inhibited by furosemide (Ki = 0.4 mM) and bumetanide. Mg2+ influx obeyed Michaelis-Menten kinetics with respect to Mg2+ concentration (Km = 1.1 mM) and was sigmoidal with respect to HCO3- concentration. Electroneutral Mg2+, HCO3- cotransport was supposed to be the mechanism of Mg2+ influx.
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002034:Bumetanide / Q000494:pharmacology; D005665:Furosemide / Q000494:pharmacology*; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism*; D009374:Neoplasms, Experimental / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology
D001639:Bicarbonates; D002034:Bumetanide; D010042:Ouabain; D000584:Amiloride; D005665:Furosemide; D008274:Magnesium