Glutamine effects on permeability and ATP content of jejunal mucosa in starved rats

Introduction: Starvation induces an increase in intestinal permeability tha t can be of importance to intestinal integrity. Glutamine is the principal energy source for intestinal enterocytes and is considered essential for gu t metabolism, structure and function. The aim of this study was to investig ate whether glutamine could improve the ATP content of the mucosa of starve d rats and attenuate the permeability perturbation during incubation in vit ro in Ussing chamber. Methods: Segments of jejunum from rats starved for 48 h were mounted in Uss ing chambers. Glutamine was added to Krebs-buffer at 0.6 mM, 3 mM, 6 mM and 30 mM concentrations on the mucosal side. Cr-EDTA permeation, ATP content of the epithelium mucosa and electrophysiology were studied during 180 min of incubation in Ussing chambers. Result: These was a negative linear correlation between ATP content and Cr- 51-EDTA permeability in stripped mucosa. ATP content was reduced in all gro ups during the experiment. When 30 mM glutamine was added on the mucosal si de there was an increase in Cr-51-EDTA permeability (P< 0.001). There was n o effect of glutamine on transepithelial resistance but higher concentratio ns of glutamine (>3 mM) significantly increased the short circuit current. Conclusion: Supplementing glutamine to the mucosal side in the Ussing chamb er led to an increase in ion pump activity and to an increase in paracellul ar permeability at the 30 mM glutamine concentration. Glutamine did not res tore the intracellular ATP level. The increase in permeability was inversel y correlated to the mucosal ATP content. (C) 1999 Harcourt Publishers Ltd.