Acute And Chronic Exposure Of Rat Intestinal Mucosa To Dextran Promotes Sglt1-Mediated Glucose Transport

Background The intestinal handling of dextran, an alpha-1,6-linked glucose polymer, is poor compared with starch, and some ingested dextran might therefore reach the lower small intestine. As luminal sugar up-regulates SGLT1 (sodium-dependent glucose transporter) locally, we report the effects of a dextran-enriched diet on jejunal and ileal brush border membrane (BBM) glucose uptake.Methods Rats were maintained on a diet containing 65% maltodextrin or 32.5% maltodextrin + 32.5% dextran (10 kD or 40 kD) for 8-10 days, and the kinetics of phlorizin-sensitive [H-3]-glucose uptake by purified BBM vesicles was determined.Results Ingestion of 40-kD but not 10-kD dextran increased V-max for jejunal and ileal glucose uptake (+64.3% and +61.8% respectively, both P<0.02). The transport response to 40-kD dextran was in keeping with lower levels of expired H-2 at the end of the feeding period. High-performance liquid chromatography (HPLC) analysis of luminal contents indicated extensive hydrolysis of ingested dextran. Finally, 3-h jejunal exposure to 40-kD dextran in vivo increased the V-max for glucose uptake by jejunal BBM.Conclusion It is likely that increased SGLT1-mediated glucose uptake after short or longer term mucosal exposure to dextran results from luminal dextran per se or a hydrolysis product. The clinical implications of this up-regulation are discussed.