Abstract
Previously, absorption of L-proline across the apical membrane of the intestinal enterocyte has been attributed to transport via the Na(+)-dependent Imino system. However, net (absorptive) transport of proline across intact Caco-2 cell monolayers was enhanced by acidification of the apical environment, under both Na(+)-containing and Na(+)-free conditions. This Na(+)-independent pH-dependent proline flux was associated with H+ flow across the apical membrane as determined by continuous measurement of intracellular pH. H+/proline symport was associated with an inward Isc in voltage-clamped Caco-2 epithelial layers demonstrating the electrogenic nature of this transport process. In conclusion Caco-2 cells possess an apically-localised, Na(+)-independent, electrogenic H+/imino acid transporter which may play an important role in intestinal proline absorption.
Original language | English |
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Pages (from-to) | 78-82 |
Number of pages | 5 |
Journal | FEBS Letters |
Volume | 333 |
Issue number | 1-2 |
Publication status | Published - 25 Oct 1993 |
Keywords
- Biological Transport
- Cell Line
- Epithelial Cells
- Epithelium
- Humans
- Hydrogen-Ion Concentration
- Intestinal Mucosa
- Proline
- Protons
- Sodium