Na+ and K+ fluxes stimulated by Na+-coupled glucose transport: evidence for a Ba2+-insensitive K+ efflux pathway in rabbit proximal tubules.
Addition of glucose or the nonmetabolizable analogue alpha-methyl-D-glucoside to rabbit proximal tubules suspended in a glucose- and alanine-free buffer caused a sustained increase in intracellular Na+ content (+43 +/- 7 nmol.(mg protein)-1) and a concomitant but larger decrease in K+ content (-72 +/- 11 nmol.(mg protein)-1). A component of the net K+ efflux was Ba2+ insensitive, and was inhibited by high (1 mM) but not low (10 microM) concentrations of the diuretics furosemide and bumetanide. The increase in intracellular Na+ content is consistent with the view that the increased rates of Na+ and water transport seen in the proximal tubule in the presence of glucose can be attributed (at least in part) to a stimulation of basolateral pump activity by an increased [Na+]i.
Avison
M J
MJ
Department of Molecular Biophysics, Yale University School of Medicine, New Haven, Connecticut.
Gullans
S R
SR
Ogino
T
T
Giebisch
G
G
D019325:3-O-Methylglucose; D000818:Animals; D001464:Barium / Q000494:pharmacology*; D002034:Bumetanide / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D004072:Digitonin / Q000494:pharmacology; D005260:Female; D005665:Furosemide / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D009682:Magnetic Resonance Spectroscopy; D008757:Methylglucosides / Q000494:pharmacology; D009004:Monosaccharide Transport Proteins / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*
D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; D002034:Bumetanide; D019325:3-O-Methylglucose; D001464:Barium; D005665:Furosemide; D012964:Sodium; D005947:Glucose; D004072:Digitonin; D011188:Potassium