Bicarbonate transport by the human pancreatic ductal cell line hpaf

Irma Demeter, Orsolya Hegyesi, Ákos Károly Nagy, Maynard R. Case, Martin C. Steward, Gábor Varga, Beáta Burghardt

Research output: Article

6 Citations (Scopus)

Abstract

OBJECTIVES:: The human pancreatic duct cell line, HPAF, has been shown previously to secrete Cl in response to Ca-mobilizing stimuli. Our aim was to assess the capacity of HPAF cells to transport and secrete HCO3. METHODS:: HPAF cells were grown as confluent monolayers on permeable supports. Short-circuit current was measured by voltage clamp. Intracellular pH (pHi) was measured by microfluorometry in cells loaded with 2′,7′-bis(2-carboxyethyl)-5(6) -carboxyfluorescein (BCECF). RESULTS:: In HCO3-free solutions, ATP-evoked changes in short-circuit current were inhibited by bumetanide, and the recovery of pHi from acid loading was abolished by 5-(N-ethyl-N-isopropyl)-amiloride (EIPA). In the presence of HCO3, ATP-evoked secretion was no longer inhibited by bumetanide, and there was a strong EIPA-insensitive recovery from acid loading, which was inhibited by 4,4′-diisothiocyanatodihydrostilbene-2,2′- disulfonate (H2DIDS). ATP, but not forskolin, stimulated HCO3 efflux from the cells. CONCLUSIONS:: In the absence of HCO3, ATP-evoked Cl secretion is driven by a basolateral Na-K-2Cl cotransporter, and pHi is regulated by apical and basolateral Na/H exchangers. In the presence of HCO3, ATP-evoked secretion is sustained in the absence of Na-K-2Cl cotransporter activity and is probably driven by basolateral Na-HCO3 cotransport.

Original languageEnglish
Pages (from-to)913-920
Number of pages8
JournalPancreas
Volume38
Issue number8
DOIs
Publication statusPublished - nov. 1 2009

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ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Hepatology
  • Endocrinology

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