BACKGROUND: Protein and mRNA levels of the hexose transporters SGLT1, GLUT2 and GLUT5 follow a daily circadian rhythm in the rat jejunum. The mechanisms regulating the expression of these important transport proteins are not known. Because vagal innervation mediates the circadian activity of other proteins in the rat small bowel our HYPOTHESIS was that circadian variation of mRNA and protein levels of SGLT1, GLUT2 and GLUT5 is mediated by vagal innervation. AIM: To determine gene and protein expression after surgical vagotomy in the rat.METHODS: 48 rats underwent either sham laparotomy (n=24) or bilateral total abdominal vagotomy (n=24). Rats were kept in a strictly maintained, alternating 12 hour light/dark room. 4 weeks postop, jejunal mucosa was harvested at 3AM, 9AM, 3PM and 9PM. At each time point, mucosa was harvested from 6 rats in each group (sham laparotomy, vagotomy). mRNA levels were determined by reverse transcription real-time PCR. Protein levels were determined by semi-quantitative Western blotting. Transporter mRNA and protein levels are expressed as a ratio of transporter gene product to the corresponding mRNA and protein levels of GAPDH, a “stably” expressed housekeeping gene. GLUT5 protein levels were unable to be measured because of unsatisfactory antibody specificity.RESULTS: Levels of mRNA for all 3 hexose transporters and protein levels of SGLT1 and GLUT2 showed circadian variation in sham controls at 4 weeks postop (p<0.03 for all). After vagotomy, the levels of SGLT1 and GLUT5 mRNA (each p<0.01) and GLUT2 mRNA (p=0.055) continued to show circadian variation. However, circadian variation in SGLT1 and GLUT2 protein levels was not observed after vagotomy (p>0.05 for both). SUMMARY: The circadian variation of SGLT1 and GLUT5 mRNA levels persisted after vagotomy. Circadian variation in SGLT1 protein levels was abolished by vagotomy. Vagotomy blunted circadian variation of GLUT2 mRNA levels and abolished the circadian variation in GLUT2 protein levels.CONCLUSIONS:Vagal innervation appears to differentially mediate the circadian changes in hexose transporter mRNA and protein expression by post-transcriptional and/or post-translational processes.