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Pflügers Archiv

, Volume 425, Issue 1–2, pp 178–180 | Cite as

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

  • David T. Thwaites
  • Gordon T. A. McEwan
  • Barry H. Hirst
  • Nicholas L. Simmons
Short Communication Molecular and Cellular Physiology

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).

Key words

Caco-2 cells dipeptide epithelia H+ symport intestine pHi short-circuit current 

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Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • David T. Thwaites
    • 1
  • Gordon T. A. McEwan
    • 1
  • Barry H. Hirst
    • 1
  • Nicholas L. Simmons
    • 1
  1. 1.Gastrointestinal Drag Delivery Research Centre, Department of Physiological SciencesUniversity of Newcastle upon Tyne, Medical SchoolNewcastle upon TyneUK

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