Intestinal Absorption of L-Glucose via Sodium/Glucose Cotransporter 1 (Sglt1) in Rats

L-Glucose is an enantiomer of D-glucose. It is controversial whether intestinal absorption of L-glucose is mediated by sodium/glucose cotransporter 1 (Sglt1). We examined whether L-glucose is absorbed via Sglt1 using KGA-2727, an Sglt1-specific inhibitor, and via glucose transporter (Glut5), a fructose transporter, using fructose-fed rats as well. KGA-2727 significantly blocked the increase of plasma L-glucose levels and lowered the C_max and AUC_{0-180 min} values. Feeding the high-fructose diet induced significantly higher intestinal Glut5 mRNA expression and higher absorption of orally administered D-fructose, but did not affect L-glucose levels and pharmacokinetic parameters. The results suggest that L-glucose is likely transported via Sglt1 in rat small intestine.