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Proximo‐distal gradient of Na + ‐dependent D‐glucose transport activity in the brush border membrane vesicles from the human fetal small intestine
Author(s) -
Malo Christiane,
Berteloot Alfred
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)80903-1
Subject(s) - phlorizin , brush border , vesicle , cotransporter , chemistry , membrane , jejunum , biophysics , d glucose , ileum , biochemistry , glucose uptake , glucose transporter , medicine , endocrinology , biology , sodium , insulin , organic chemistry
Brush‐border membrane vesicles were isolated from the jejunum and ileum of 17–20‐week‐old normal human fetuses and found to be highly enriched in sucrase activity with less than 5% contamination by basolateral membranes. Time course studies of D‐glucose uptake clearly showed a transient, phlorizin‐sensitive, and Na + ‐dependent accumulation of sugar into these vesicles. Higher maximum overshoot values and initial rates of D‐glucose uptake were recorded in jejunal as compared to ileal vesicles while low substrate binding to the membranes, identical intravesicular volumes and equivalent dissipation of the Na + ‐gradient were found in the two preparations. It was concluded that a fully functional Na + ‐D‐glucose cotransport system is present with a proximo‐distal gradient of activity during the early gestation period.