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Pflugers Arch. 1993 Oct;425(1-2):178-80.

Transepithelial dipeptide (glycylsarcosine) transport across epithelial monolayers of human Caco-2 cells is rheogenic.

Author information

1
Department of Physiological Sciences, University of Newcastle upon Tyne, Medical School, UK.

Abstract

Net transepithelial transport (and cellular accumulation) of the dipeptide glycylsarcosine (Gly-Sar), across the apical membrane of human intestinal Caco-2 epithelia, is driven by a proton gradient (Na(+)-free conditions) and displays saturation kinetics (Km 17.4 +/- 5.1 mM, Vmax of 92.8 +/- 15.6 nmol.cm-2.h-1). Net Gly-Sar transport is associated with the stimulation of an inward short-circuit current (Isc). This dipeptide-stimulated Isc is observed in both Na(+)-containing and Na(+)-free conditions, is stimulated by apical acidity, and displays saturation kinetics (in Na(+)-free media at apical pH 6.0, Km of 13.6 +/- 4.5 mM and a Vmax of 284.1 +/- 39.3 nmol.cm-2.h-1). The maximal capacities of Gly-Sar transport and Isc suggest a dipeptide/proton stoichiometry greater than unity (1:3).

PMID:
8272376
DOI:
10.1007/bf00374520
[Indexed for MEDLINE]

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