Plasma membrane studies on drug-sensitive and -resistant cell lines. II. Ouabain sensitivity of (Na+ +K+)-stimulated Mg2+-ATPase.
Mutant cell lines have been selected from the murine plasmocytoma MOPC 173 for their resistance to ouabain, dibutyryl cyclic AMP, theophyllin and concanavalin A. We have compared three wild-type cell lines with their seven resistant counterparts. All resistant mutants exhibited a (Na+ + K+)-stimulated Mg2+-ATPase resistance to ouabain inhibition when measured in microsomes. The homogeneity of ouabain binding sites has been found in most of the cell lines; however, two different populations of sites have been detected in one wild-type and in one resistant cell lines. These results led us to hypothetise the (Na+ + K+)-ATPase-ouabain interaction being modulated by a non-specific membrane structure.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D003208:Concanavalin A / Q000494:pharmacology; D004351:Drug Resistance; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology*; D013806:Theophylline / Q000494:pharmacology
D003208:Concanavalin A; D010042:Ouabain; D003994:Bucladesine; D012964:Sodium; D013806:Theophylline; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium