pH-dependent fluoride transport in intestinal brush border membrane vesicles

Han He, Vadivel Ganapathy, Carlos M Isales, Gary M. Whitford

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Fluoride (F) absorption from the rat stomach and urinary bladder, hamster cheek pouch, and the renal tubules of several species are pH gradient-dependent. These observations led to the hypothesis that F crosses these epithelia in the form of the undissociated acid, HF. Several recent reports, however, have provided evidence that F absorption from the rat small intestine is insensitive to the lumenal pH. We report here our evidence that F uptake by rabbit intestinal brush border membrane vesicles (BBMV) occurred rapidly and with an overshoot only in the presence of an inward-directed proton gradient. In the absence of a proton gradient or in the presence of an outward-directed gradient, F uptake was slow and without an overshoot. In the presence of an inward-directed proton gradient, F uptake was partially inhibited by DIDS and DEP but not by diBAC. PCMBS inhibited F uptake by up to 83% in a dose-response manner. DiBAC appeared to reduce intravesicular pH slightly but the other reagents had no effect. When the uptake buffer contained chloride or nitrate, F uptake was partially inhibited compared to the mannitol or gluconate controls. It was concluded that F transport across the rabbit intestinal BBMV occurs via a carrier-mediated process which may involve cotransport of F with H+ or exchange of F with OH-. The inhibitory effects of DIDS, DEP and PCMBS may occur by affecting this carrier-mediated transport. Copyright (C) 1998 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)244-254
Number of pages11
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1372
Issue number2
DOIs
StatePublished - Jul 17 1998

Keywords

  • 4,4'-Diisothiocyanostilbene-2,2'-disulfonate
  • Absorption
  • Diethylpyrocarbonate
  • Fluoride
  • p-Chloromercuribenzene sulfonate
  • pH gradient

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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