FASULO, V.; CAVIEDES-VIDAL, E.*; KARASOV, W.H.: In vivo modulation of intestinal paracellular absorption by mediated glucose transport

D-glucose is absorbed along two paths: paracellular and transcellular. The transcellular path is mediated by an active cotransport system (SLGT1) and a non-active transport system (GLUT2). Luminal presence and absorption of some substances (e.g., D-glucose) through the apical membrane of enterocytes has been shown to increase the magnitude of the paracellular absorption of D-glucose and other hydrosoluble compounds. In this study we evaluate the contribution of the two mediated transport systems used by D-glucose on the paracellular absorption of L-arabinose. Eight Wistar rats were each administered by intestinal cannula randomly with five solutions (Ti) containing L-arabinose as an intestinal permeability marker and, T1: D-glucose; T2: D-mannitol; T3: D-glucose + phloridzin (SGLT1 inhibitor); T4: D-glucose + phloridzin + phloretin (GLUT2 inhibitor); T5: D-mannitol + phloridzin + phloretin. Serial blood samples were taken both after intestinal administration and intramuscular injection of arabinose. Bioavailability of the pentose was estimated by its plasma concentration using standard pharmacokinetic methodology. L-arabinose bioavailability was T1:39±3%; T2:14±1%; T3:34±2%; T4: 20±2%; T5: 13±2% (T5=T4=T2<T3=T1). Thus, modulation of paracellular absorption of hydrosoluble compounds is partly influenced by phloretin sensitive D-glucose transport. Granted by FONCYT PICT98 01-3101 and CyT UNSL to EC-V and NSF IBN-9723793 to WHK.