Coordinated, diurnal hexose transporter expression in rat small bowel: Implications for small bowel resection

Scott G. Houghton, Corey W. Iqbal, Judith A. Duenes, Javairiah Fatima, Michael S. Kasparek, Michael G. Sarr

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Background: Hexose transporter mRNA and protein levels follow a diurnal rhythm in rat jejunum. Their coordinated expression and resultant function throughout the small bowel is not well understood. We hypothesized that hexose transporter levels and glucose absorption follow a coordinated, site-specific diurnal rhythm in rat duodenum and jejunum, but not in ileum. Methods: Sprague-Dawley rats were housed in a strictly maintained, 12-h, light/dark room [light 6 am to 6 pm] with free access to water and chow. Mucosa was harvested from duodenum, jejunum, and ileum at 3 am, 9 am, 3 pm, and 9 pm, and full thickness 1-cm segments were harvested at 9 am, and 9 pm (n = 6 for each segment at each time point). mRNA levels were determined by reverse-transcription, real-time polymerase chain reaction (n ≥ 5), protein levels by semiquantitative Western blotting (n ≥ 5), and transporter-mediated glucose uptake by everted sleeve technique (n = 6). Results: mRNA levels of SGLT1 and GLUT5 followed a temporally coordinated, diurnal rhythm in all 3 segments (P < .01), while mRNA for GLUT2 and protein levels for SGLT1 and GLUT2 varied diurnally only in duodenum and jejunum (P > .05) but not in ileum (P > .10). SGLT1 and GLUT5 mRNA induction decreased aborally. Baseline SGLT1 and GLUT5 mRNA levels and SLGT1 and GLUT2 protein levels did not vary aborally (P > .05 for all). GLUT2 mRNA baseline levels were decreased in ileum (P < .01). Glucose uptake varied diurnally in duodenum and jejunum with no difference in ileum. Transporter-mediated glucose uptake was greater in duodenum and jejunum compared with ileum. Conclusion: Regulation of hexose absorption in rat small bowel seems to be site-specific and mediated by multiple mechanisms.

Original languageEnglish (US)
Pages (from-to)79-93
Number of pages15
Issue number1
StatePublished - Jan 2008

ASJC Scopus subject areas

  • Surgery


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