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Bombesin maintains enterocyte phenotype in fasted rats
1Department of Surgery, Beth Israel Hospital, Harvard Medical School, Harvard Digestive Diseases Center, Boston, MA 02215.
Surgery
|August 1, 1994
Summary
The intestinal peptide bombesin alters brush-border enzyme expression in rats. Bombesin decreases lactase and increases intestinal alkaline phosphatase (IAP) mRNA, supporting a link between epithelial growth and cell phenotype.
Area of Science:
- Gastroenterology
- Molecular Biology
- Cell Biology
Background:
- Enterocyte phenotype correlates with epithelial growth state.
- High lactase and low intestinal alkaline phosphatase (IAP) expression occur in atrophic conditions.
- Low lactase and high IAP expression are observed in hyperplastic states.
Purpose of the Study:
- To investigate the effect of the intestinal trophic factor bombesin on brush-border enzyme gene expression.
- To test the hypothesis that bombesin alters enterocyte phenotype in a predictable manner.
Main Methods:
- Adult rats were treated with bombesin or saline after fasting.
- Small intestinal mucosal RNA was extracted for Northern blot analysis.
- Lactase, IAP, villin, and actin mRNA levels were quantified.
- Jejunal mucosal thickness was measured.
Main Results:
- Bombesin increased jejunal mucosal thickness, confirming its trophic effect.
- Bombesin decreased lactase mRNA and increased IAP mRNA throughout the small intestine.
- No significant changes in villin or actin mRNA were observed.
Conclusions:
- Bombesin differentially regulates enterocyte gene expression in rats.
- Bombesin treatment leads to decreased lactase and increased IAP mRNA levels.
- Results support a strong relationship between enterocyte phenotype and epithelial growth state.