PMID: 9545565May 16, 1998Paper

Transport mechanisms of a glycoside, p-nitrophenyl-beta-D-glucopyranoside, across rat small intestinal brush-border membranes

Biochimica Et Biophysica Acta
T OhnishiS Awazu

Abstract

We examined the mechanism of p-nitrophenyl-beta-d-glucopyranoside (p-NP-beta-d-Glc) transport in brush-border membrane vesicles from rat small intestine. The initial uptake rate showed an overshoot phenomenon in the presence of an inwardly directed sodium-ion concentration gradient. The overshoot disappeared when the sodium-ion concentration gradient was replaced with a potassium ion concentration gradient. d-Glucose and p-NP-beta-D-Glc analogues inhibited the uptake, whereas uridine, leucine and disaccharide did not. Data on the concentration dependence of p-NP-beta-D-Glc uptake indicated that two carrier-mediated systems are involved. The uptake via the high-affinity site required an inwardly directed sodium-ion concentration gradient, while the uptake via the low-affinity site proceeded such a gradient. D-Glucose competitively inhibited the initial uptake of p-NP-beta-D-Glc via the high-affinity site with a Ki value of 301 microM. The p-NP-beta-D-Glc is transported in the small intestine via both the same carrier-mediated transport system that takes up D-glucose and a distinct low-affinity carrier-mediated transport system.

References

Nov 1, 1994·The Journal of Membrane Biology·M P LostaoE M Wright
Sep 30, 1994·Biochemical and Biophysical Research Communications·T MizumaS Awazu
Jul 13, 1994·Biochimica Et Biophysica Acta·B HirayamaG E Kisby
Nov 17, 1993·Biochemical Pharmacology·Y WangC Bowmer

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Citations

Nov 22, 2005·Expert Opinion on Drug Delivery·Isabel Gomez-Orellana
Dec 25, 2004·Drug Metabolism and Pharmacokinetics·Mitsuru SugawaraKatsumi Miyazaki
Nov 12, 2005·Annals of Nutrition & Metabolism·Christiane StarpPeter Stehle

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