title: Upregulation of intestinal NHE3 following saline ingestion.
abstract: BACKGROUND
  Little is known about the effect of salt content of ingested fluid on intestinal transport processes. Osmosensitive genes include the serum- and glucocorticoid-inducible kinase SGK1, which is up-regulated by hyperosmolarity and cell shrinkage. SGK1 is in turn a powerful stimulator of the intestinal Na(+)/H(+) exchanger NHE3. The present study was thus performed to elucidate, whether the NaCl content of beverages influences NHE3 activity.
  
  
  METHODS
  Mice were offered access to either plain water or isotonic saline ad libitum. NHE3 transcript levels and protein abundance in intestinal tissue were determined by confocal immunofluorescent microscopy, RT-PCR and western blotting, cytosolic pH (pHi) in intestinal cells from 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) fluorescence and Na(+)/H(+) exchanger activity from the Na(+) dependent realkalinization following an ammonium pulse.
  
  
  RESULTS
  Saline drinking significantly enhanced fluid intake and increased NHE3 transcript levels, NHE3 protein and Na(+)/H(+) exchanger activity.
  
  
  CONCLUSIONS
  Salt content of ingested fluid has a profound effect on intestinal Na(+)/H(+) exchanger expression and activity.
authors.affiliation: Department of Physiology, University of Tübingen, Tübingen, Germany.
authors.forename: Venkanna
authors.initials: V
authors.lastname: Pasham
authors.forename: Anand
authors.initials: A
authors.lastname: Rotte
authors.forename: Shuchen
authors.initials: S
authors.lastname: Gu
authors.forename: Wenting
authors.initials: W
authors.lastname: Yang
authors.forename: Madhuri
authors.initials: M
authors.lastname: Bhandaru
authors.forename: Rexhep
authors.initials: R
authors.lastname: Rexhepaj
authors.forename: Ganesh
authors.initials: G
authors.lastname: Pathare
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000818:Animals; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D005260:Female; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D009924:Organ Culture Techniques; D012965:Sodium Chloride / Q000008:administration & dosage*; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000096:biosynthesis*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*
chemical_list: C000613386:Slc9a3 protein, mouse; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D012965:Sodium Chloride