Glutamine reduces phorbol-12,13-dibutyrate-induced macromolecular hyperpermeability in HT-29Cl.19A intestinal cells.
BACKGROUND
Loss of mucosal integrity is associated with intestinal hyperpermeability, which may be inhibited by glutamine. The nature of this effect is unknown. The effect of glutamine on protein kinase C (PKC)-mediated hyperpermeability in HT-29Cl.19A intestinal cells was studied.


METHODS
Confluent monolayers of HT-29C1.19A cells were cultured on permeable filters and mounted in Ussing chambers for permeability studies. Apical to basolateral transepithelial permeability for intact horseradish peroxidase (HRP) was determined. Phorbol-12,13-dibutyrate (PDB) was used to activate PKC-mediated hyperpermeability, and the effect of glutamine (0.6 mmol/L) was studied.


RESULTS
Two hours of PDB stimulation increased the HRP flux, reaching five times control values after 4 hours. Bilateral exposure to glutamine for 4 hours reduced PDB-induced hyperpermeability (37%). Preincubation with glutamine 2 hours before PDB stimulation showed an earlier and greater effect (3 hours, 43%; 4 hours, 50%). This bilateral effect of glutamine was mimicked by separate apical exposure. Basolateral exposure alone had no effect.


CONCLUSIONS
Glutamine rapidly reduced the PKC-mediated hyperpermeability for HRP in HT-29Cl.19A intestinal cells. The dependency on apical exposure suggests that glutamine may be more effective when delivered by the enteral route.
Kouznetsova
L
L
Department of Surgery, Free University Hospital, Amsterdam, Institute of Neurobiology, Faculty of Biology, University of Amsterdam, The Netherlands.
Bijlsma
P B
PB
van Leeuwen
P A
PA
Groot
J A
JA
Houdijk
A P
AP
D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004847:Epithelial Cells / Q000648:ultrastructure; D005973:Glutamine / Q000378:metabolism / Q000494:pharmacology*; D006735:Horseradish Peroxidase / Q000378:metabolism; D006801:Humans; D007422:Intestines / Q000648:ultrastructure*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism
D005973:Glutamine; D015240:Phorbol 12,13-Dibutyrate; D006735:Horseradish Peroxidase; D011493:Protein Kinase C