Effects of acetate on luminal acidification processes in the S3 segment of the rabbit proximal tubule.
We determined that, in the nominal absence of HCO-3, acetate (Ac-) doubles luminal acidification in the S3 segment of the rabbit proximal tubule. This stimulation had two components, one that was dependent on Na+ and luminal Ac- and a second that was independent of Na+ but dependent on basolateral Ac-. In the presence of 25 mM HCO-3, Ac- did not stimulate acid secretion (i.e., HCO-3 reabsorption), but actually inhibited it. The inhibition was 35% with bilateral Ac- and 15% with basolateral Ac-. The effects of Ac- were reversible both in the absence and presence of HCO-3, and are present at concentrations as low as 1 mM. We conclude that acetate (i.e., monocarboxylates) has a significant effect on luminal acidification processes both in the presence and absence of HCO-3.
Geibel
J
J
Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510.
Giebisch
G
G
Boron
W F
WF
D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000494:pharmacology; D000085:Acetates / Q000494:pharmacology*; D000818:Animals; D001639:Bicarbonates / Q000652:urine; D004594:Electrophysiology / Q000379:methods; D004848:Epithelium / Q000502:physiology; D005260:Female; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials; D008839:Microelectrodes; D008962:Models, Theoretical; D011817:Rabbits
D000085:Acetates; D001639:Bicarbonates; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid