Bicarbonate stimulation of Na+ transport in liver basolateral plasma membrane vesicles requires the presence of a transmembrane pH gradient.
The effect of bicarbonate on the uptake of 22Na+ into liver basolateral plasma membrane vesicles was studied under conditions where the pH of the medium was controlled by the use of high buffer concentrations. Bicarbonate stimulated the rate of Na+ uptake only in the presence of a pH gradient (acid inside). The stimulation by bicarbonate was inhibited by both amiloride and DIDS. No evidence for electrogenic Na+/HCO3- symport was found. These results are in part consistent with electroneutral Na+/HCO3- symport, but other explanations cannot be excluded.
Felipe
A
A
Department of Biochemistry, School of Medical Science, University Walk, Bristol, U.K.
Moule
S K
SK
McGivan
J D
JD
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000031:analogs & derivatives*; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology*; D001692:Biological Transport; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D017693:Sodium Bicarbonate
D001639:Bicarbonates; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; C018564:dihydro-DIDS; D000584:Amiloride; D017693:Sodium Bicarbonate; D012964:Sodium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid