Luminal regulation of Na(+)/H(+) exchanger gene expression in rat ileal mucosa.
J Gastrointest Surg
; 6(3): 387-95, 2002.
Article
em En
| MEDLINE
| ID: mdl-12022991
ABSTRACT
It is well recognized that ileostomy patients suffer from chronic depletion of Na(+) through the stoma effluent. In this study we evaluated the effects of ileostomy on messenger RNA levels that encode different Na(+)/H(+) exchanger isoforms (NHE-2 and NHE-3). Loop ileostomies were created in Sprague-Dawley rats. Segments of diverted ileum were harvested for quantitation of mRNA levels encoding these isoforms and the Na(+)/K(+) ATPase in mucosal scrapings and for immunofluorescence microscopy, specifically of the NHE-3 protein. Our studies indicate that as early as 8 days after diversion, NHE-3 gene expression is selectively attenuated in poststomal ileal mucosa. Mucosal morphology remains undisturbed, and the distribution of protein expression along the crypt/villus axis is not altered. Infusion of Na(+) or the enterocyte nutrient, glutamine, into the lumen of the diverted segment restores or even augments mRNA levels for NHE-3, again without altering the histologic appearance or distribution of the protein along the crypt/villus axis. These effects are specific because nonpolar osmolytes (mannitol) and related organic nutrients not specific for the enterocyte (i.e., butyrate) have no effect on mRNA levels of NHE-3. Further work is required to understand how the early changes in mRNA contribute to mucosal function and response to luminal diversion.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ileostomia
/
Regulação da Expressão Gênica
/
Trocadores de Sódio-Hidrogênio
/
Íleo
/
Mucosa Intestinal
Limite:
Animals
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article