In situ intestinal absorption of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid in guinea pigs.
The intestinal absorption efficacy of 2-O-alpha-D-glucopyranosyl-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 alpha-glucosidase inhibitor, or by carbohydrates such as maltose. These results indicate that ascorbic acid released from AA-2G by alpha-glucosidase on the brush border membrane is effectively taken up across the intestinal ascorbate transport channels, into a serosal site, whereas AA-2G permeation was poor via the passive transport system.
Wakamiya
H
H
Division of Human Science and Technology, Ochanomizu University, Tokyo, Japan.
Suzuki
E
E
Yamamoto
I
I
Akiba
M
M
Arakawa
N
N
D000818:Animals; D001205:Ascorbic Acid / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics; D002241:Carbohydrates / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D065089:Glycoside Hydrolase Inhibitors; D006168:Guinea Pigs; D006868:Hydrolysis / Q000187:drug effects; D007212:Indolizines / Q000494:pharmacology; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology*; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008320:Maltose / Q000494:pharmacology; D054836:Indolizidines
D001205:Ascorbic Acid; D002241:Carbohydrates; D004791:Enzyme Inhibitors; D065089:Glycoside Hydrolase Inhibitors; D007212:Indolizines; D008320:Maltose; C065378:ascorbic acid 2-O-glucoside; C037806:castanospermine; D054836:Indolizidines