Effects of ouabain and osmolarity on bumetanide-sensitive potassium transport in simian virus-transformed 3T3 cells.
Unidirectional potassium influx in simian virus-transformed 3T3 cells was dissected into a ouabain-inhibitable "pump' component, a bumetanide-sensitive and chloride-dependent "cotransport' component, and a residual "leak' flux. The bumetanide-sensitive component was stimulated 2-3-fold by a 60-min preincubation with ouabain. Subsequent washing of the cells and incubation in ouabain-free saline reversed both the inhibition of the Na+ pump and the stimulation of bumetanide-sensitive flux. Bumetanide-sensitive potassium influx was also stimulated by hypertonic cell shrinkage (induced by 0.1 M or 0.2 M sorbitol). This latter observation suggests that the bumetanide-sensitive system may play a role in cellular volume regulation.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002034:Bumetanide / Q000494:pharmacology*; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D004232:Diuretics / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism*; D012413:Rubidium / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics*
D004232:Diuretics; D002034:Bumetanide; D010042:Ouabain; D012413:Rubidium; D011188:Potassium