title: Insulin activates furosemide-sensitive K+ and Cl- uptake system in BC3H1 cells.
abstract: Insulin augments the activity of Na(+)-K(+)-adenosinetriphosphatase (ATPase) in skeletal muscles. This study shows that when furosemide- and bumetanide-inhibitable 86Rb+ uptake is measured in the skeletal muscle-like BC3H1 cell line, insulin and insulin-like growth factor I (IGF-I) activate a loop diuretic-sensitive K+ and Cl- transport system but have no effect on Na(+)-K(+)-ATPase. The insulin-stimulated K+ transport system is extracellular Na+ concentration ([Na+]o) independent and extracellular Cl- concentration ([Cl-]o) dependent. Na(+)-independent K(+)-Cl- cotransport systems have been identified in other cells, but their sensitivity to insulin or growth factors has not been described. The affinities of the insulin-stimulated K+ uptake in BC3H1 cells for K+ (0.9 +/- 0.1 mM) and loop diuretics (5.9 x 10(-7) and 10(-7) M for furosemide and bumetanide, respectively) are higher than those of K(+)-Cl- cotransporters in other cells. Thus the insulin-stimulated K+ and Cl- transport system in BC3H1 seems kinetically different from K(+)-Cl- cotransporters in other cells. Insulin and IGF-I may activate a unique K(+)-Cl- cotransporter or activate a [Na+]o-independent K(+)-Cl- cotransport mode of Na(+)-K(+)-Cl- cotransporter in BC3H1 cells.
authors.affiliation: Department of Pharmacology, Hebrew University of Jerusalem, School of Pharmacy, Faculty of Medicine, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Weil-Maslansky
authors.forename: Y
authors.initials: Y
authors.lastname: Gutman
authors.forename: S
authors.initials: S
authors.lastname: Sasson
mesh_terms: D000818:Animals; D001692:Biological Transport; D002454:Cell Differentiation; D002460:Cell Line; D002712:Chlorides / Q000493:pharmacokinetics*; D005260:Female; D005665:Furosemide / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000493:pharmacokinetics*; D051381:Rats
chemical_list: D002712:Chlorides; D007328:Insulin; D010042:Ouabain; D007334:Insulin-Like Growth Factor I; D005665:Furosemide; D011188:Potassium