Proximal Tubular Cell Alkalinization Induced by Na+-Glucose Cotransport.

NHE3-dependent cytoplasmic alkalinization is triggered by Na(+)-glucose cotransport in intestinal epithelia.

Cytoplasmic pH (pH(i)) was evaluated during Na(+)-glucose cotransport in Caco-2 intestinal epithelial cell monolayers. The pH(i) increased by 0.069 +/- 0.002 within 150 s after initiation of Na(+)-glucose cotransport. This increase occurred in parallel with glucose uptake and required expression of the intestinal Na(+)-glucose cotransporter SGLT1. S-3226, a preferential inhibitor of Na(+)/H(+) ...

Molecular biology of Na+/glucose cotransport.

Partial purification and reconstitution of the Na+-D-glucose cotransport protein from pig renal proximal tubules.

Brush border membranes from renal proximal tubules were solubilized with deoxycholate, and the proteins were incorporated into liposomes formed from cholesterol and phosphatidylserine by a freeze-thaw procedure. In the proteoliposomes Na+-D-glucose cotransport was demonstrated by showing that the D-glucose concentration in the liposomes increased far above the equilibrium value if a Na+ gradien...

Heat shock-induced protection and enhancement of Na+-glucose cotransport by LLC-PK1 monolayers.

Monolayers of the porcine-derived renal epithelial cell line, LLC-PK1, were used to characterize the effects of heat stress on Na+-glucose cotransport. Transepithelial current dependent on 5 mM glucose ( I Glc), phloridzin-sensitive current ( I phz), and total transepithelial current ( I total) were measured as indicators of Na+-glucose cotransport. Severe heat shock (SHS; 45°C for 1 h, then 37...

Coordinate modulation of Na-K-2Cl cotransport and K-Cl cotransport by cell volume and chloride.

Na-K-2Cl cotransporter (NKCC) and K-Cl cotransporter (KCC) play key roles in cell volume regulation and epithelial Cl(-) transport. Reductions in either cell volume or cytosolic Cl(-) concentration ([Cl(-)](i)) stimulate a corrective uptake of KCl and water via NKCC, whereas cell swelling triggers KCl loss via KCC. The dependence of these transporters on volume and [Cl(-)](i) was evaluated in m...