1995 Volume 41 Issue 2 Pages 265-272
The intestinal absorption efficacy of 2-O-α-D-glucopyrano-syl-L-ascorbic acid (AA-2G), which has been recently synthesized and characterized as a stable ascorbate (ASA), was determined in guinea pigs by the perfusion technique. Perfusion of AA-2G in isotonic phosphate buffer to the small intestine resulted in a decrease of AA-2G accompanied by an increase of AsA in the perfusate. The results showed that intact AA-2G was not detected in the plasma of the portal vein of guinea pigs at 2 h after perfusion. The disappearance of AA-2G from perfusate was completely inhibited by the addition of castanospermine, a specific a-glucosidase inhibitor, or by carbohydrates such as maltose. These results indicate that ascorbic acid released from AA-2G by a-glucosidase on the brush border membrane is effectively taken up across the intestinal ascorbate transport channels, into a serosal site, whereas AA-2G permea-tion was poor via the passive transport system.
