Tumor necrosis factor alpha (TNF-alpha) is a mediator of many metabolic and physiologic responses during septic shock. Previous studies from our laboratory have revelated that TNF-alpha inhibits D-fructose intestinal absorption by reduction on GLUT5 levels. With the purpose to amplify this knowledge, we examined the effect of this cytokine on the gastrointestinal tract physiology. To try the TNF-alpha action on epithelial cell integrity, the morphology of intestinal membrane was examined by electron microscopy and we also studied DNA laddering pattern in enterocytes of both control and TNF-alpha treated animals. The results showed that TNF-alpha treatment did not affect the structure of intestinal mucosa and not produce DNA fragmentation confirming the absence of apoptosis in the jejunum. However, the TNF-alpha had functional effects on gut as show the inhibition on D-fructose uptake in the brush border memebrane vesicles (BBMV). The mechanism of this inhibition does not seem to be transcriptional since GLUT5 mRNA levels, evaluated by Northern blot, were similar in both animals groups. Handling, equipment and killing of animals was in accordance with the European Council Legislation 86/609/EEC concerning experimental animal protection.

Acknowledgements: The rabbit polyclonal antibody GLUT5 was kindly provided by Dr. E. Brot-Laroche (INSERM U505, Paris, France) and G.I. Bell (Howard Hughes Medical Institute, Chicago University, Chicago, IL, USA). This work was supported by grants from AGL 2003-04497/GAN (PGE+FEDER) and Departamento de Ciencia, Tecnología y Universidad del Gobierno de Aragón (Spain) A-32.. This group is member of the Network for Cooperative Research on Membrane Transport Proteins (Grant BFU2005-24983-E/BFI).