Dynamic regulation of GLUT2 at the enterocyte brush border membrane (BBM) provides a high capacity route for post-prandial dietary glucose absorption. Over the past decade significant advances have been made in our understanding of the mechanisms by which GLUT2 is trafficked to the BBM (Kellett et al., 2008). There is less information on the processes involved in GLUT2 internalisation; however, using cultured intestinal epithelial cells it has recently been shown that activation of the P2X7 receptor reduces membrane levels of this protein (Bourzac et al., 2012). The present study investigated the putative role of the P2X7 receptor in regulating intestinal GLUT2 internalisation in vivo. Male wild-type (WT) and P2X7-/- mice (~25g) were terminally anaesthetised with 50mg/kg-1 sodium pentobarbitone (i.p) and 10cm segments of proximal small intestine were cannulated in vivo. These were perfused with Krebs buffer containing 75mM glucose, oxygenated with 95%O2:5%CO2 to create segmental flow at a rate of 1ml/min. The intestine was removed and placed in an organ chamber at 37°C and allowed to equilibrate for 30 mins. Serosal fluid was collected after an additional 30 mins (control period, C) and 30 mins after the solution was switched to one containing either 10mM glucose, 1mM Phloretin, a competitive inhibitor of GLUT2 or 100µM BzATP, a P2X7 agonist (experimental period, E). Serosal fluid volume was recorded and glucose concentration measured using a colorimetric assay. Results are expressed in µmoles/cm small intestine/min (Mean ± SEM) using 7 animals per group: statistical significance was tested using a paired t-test. In WT animals, glucose absorption was decreased by switching the perfusate from 75mM to 10mM glucose (C: 124.2±20.8 vs. E: 78.0±14.4, P<0.05), indicating rapid loss of GLUT2 expression after removing the high glucose stimulus. The reduction in transport induced by Phloretin (C: 144.8±14.4 vs. E: 51.9±10.5, P<0.05) confirmed the contribution of GLUT2-mediated transport at 75mM glucose. In contrast, in P2X7-/- mice glucose absorption was unaffected by reducing glucose concentration (C: 132.3±12.1 vs. E: 136.4±8.6), suggesting that GLUT2 remains at the BBM. In WT animals addition of 100µM BzATP to the 75mM perfusate reduced glucose absorption (C: 186.7±28.6 vs. E: 128.9± 18.1, P<0.05), also indicating the involvement of P2X7 in GLUT2 internalisation. Taken together these data suggest a role for the P2X7 receptor in controlling GLUT2 expression at the enterocyte BBM in vivo. Since GLUT2 is permanently expressed at the BBM in diabetes, and probably contributes to hyperglycaemia, this pathway may be a novel target to improve glycaemic control in diabetic patients.