Luminal Osmolarity Downregulates Gene Expression of Na+/H+ Exchanger (NHE3) in Rat Colon Mucosa

Marc A. Doble, Vicky B. Tola, Robert R. Cima, Michael J. Zinner, Michael A. Klein, David I. Soybel

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Water-coupled Na+ absorption in the colon is mediated principally by Na+/H+ exchange (isoforms NHE2 and NHE3). To determine whether luminal ion composition or osmolarity influences NHE expression in colon mucosa, two groups (n = 6 in each) of adult male Sprague-Dawley rats underwent sham laparotomy or loop ileostomy. In these studies, diversion did not markedly alter mRNA levels for NTHE2, NHE3, or Na+/K+, at 8 or 21 days, indicating that loss of luminal volume does not alter NHE gene expression. To evaluate the effects of specific luminal components, we infused equal volumes of half-normal (154 mOsm) or iso-osmolar (308 mOsm) solutions of saline and mannitol into the diverted colon. All solutions elicited significant (45% to 60%; P <0.05) decreases in mRNA levels for NHE3, with iso-osmolar mannitol eliciting the greatest changes. Decreases in NHE2 and Na+/K+ mRNA levels were observed following these infusions but were not as marked as the changes for NHE3. These findings suggest that (1) loss of luminal Na+ is not, in itself, a signal that regulates NHE expression and (2) infusion of any solute, including Na+ itself, provides a signal to downregulate expression of NHE3 in colon mucosa.

Original languageEnglish (US)
Pages (from-to)531-535
Number of pages5
JournalJournal of Gastrointestinal Surgery
Volume4
Issue number5
DOIs
StatePublished - Jan 1 2000

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Sodium-Hydrogen Antiporter
Osmolar Concentration
Colon
Mucous Membrane
Down-Regulation
Gene Expression
Mannitol
Messenger RNA
Ileostomy
Sodium Chloride
Laparotomy
Sprague Dawley Rats
Protein Isoforms
Ions
Water

All Science Journal Classification (ASJC) codes

  • Surgery
  • Gastroenterology

Cite this

Doble, Marc A. ; Tola, Vicky B. ; Cima, Robert R. ; Zinner, Michael J. ; Klein, Michael A. ; Soybel, David I. / Luminal Osmolarity Downregulates Gene Expression of Na+/H+ Exchanger (NHE3) in Rat Colon Mucosa. In: Journal of Gastrointestinal Surgery. 2000 ; Vol. 4, No. 5. pp. 531-535.
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Luminal Osmolarity Downregulates Gene Expression of Na+/H+ Exchanger (NHE3) in Rat Colon Mucosa. / Doble, Marc A.; Tola, Vicky B.; Cima, Robert R.; Zinner, Michael J.; Klein, Michael A.; Soybel, David I.

In: Journal of Gastrointestinal Surgery, Vol. 4, No. 5, 01.01.2000, p. 531-535.

Research output: Contribution to journalArticle

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