The beta-anomeric and glucose preferences of glucose transport carrier for intestinal active absorption of monosaccharide conjugates.
The anomeric preference for intestinal absorption of glucosides and galactosides (1- and 2-naphthyl glycosides) was studied by the everted rat intestine method. After the absorption of beta-glucoside and beta- and alpha-galactosides, the glycosides itself appeared on the serosal side, whereas after the alpha-glucoside absorption, the glucoside itself was not detected on the serosal side, but a large amount of aglycone appeared instead. This indicates an alpha-anomeric preference of desglucosylation through the intestinal membrane. A significant decrease of the total (glycoside + aglycone + glucuronide metabolites) amount transported to the serosal side in the absence of Na+, a cosubstrate of the glucose transport carrier (GTC), was observed in alpha- and beta-glucosides and beta-galactoside, but not in alpha-galactoside. This indicates the poor contribution of GTC to the alpha-galactoside absorption. The Na(+)-dependent absorption of the glycosides by the GTC were beta-glucoside > alpha-glucoside > beta-galactoside (for 2-naphthyl glycosides), and beta-galactoside > alpha-galactoside (for 1-naphthhyl glycosides). These results and those of a previous study led to the conclusion that the intestinal glucose transport carrier prefers beta-anomer to alpha-anomer, and glucose to galactose for monosaccharide conjugates absorption.
Department of Biopharmaceutics, Tokyo College of Pharmacy, Japan.
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Mizuma
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Ohta
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Awazu
D000818:Animals; D001692:Biological Transport; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005960:Glucosides / Q000378:metabolism; D005965:Glucuronates / Q000378:metabolism; D006027:Glycosides / Q000378:metabolism; D066298:In Vitro Techniques; D007408:Intestinal Absorption; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013379:Substrate Specificity
D005960:Glucosides; D005965:Glucuronates; D006027:Glycosides; D009004:Monosaccharide Transport Proteins; C037277:1-naphthylglucoside; C088461:2-naphthylglucoside; C029091:naphthyl glucuronide; D005947:Glucose; D005690:Galactose