TY - JOUR
T1 - Coordinated, diurnal hexose transporter expression in rat small bowel
T2 - Implications for small bowel resection
AU - Houghton, Scott G.
AU - Iqbal, Corey W.
AU - Duenes, Judith A.
AU - Fatima, Javairiah
AU - Kasparek, Michael S.
AU - Sarr, Michael G.
PY - 2008/1
Y1 - 2008/1
N2 - 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.
AB - 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.
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U2 - 10.1016/j.surg.2007.06.007
DO - 10.1016/j.surg.2007.06.007
M3 - Article
C2 - 18154936
AN - SCOPUS:37249085153
SN - 0039-6060
VL - 143
SP - 79
EP - 93
JO - Surgery
JF - Surgery
IS - 1
ER -