Effect of lipopolysaccharide on D-fructose transport across rabbit jejunum.
OBJECTIVE
To investigate alterations in the transport of D-fructose across the rabbit jejunum when the gut is exposed in vitro to lipopolysaccharide (LPS), an endotoxin causative agent of sepsis.


METHODS
D-fructose intestinal transport was assesed employing three techniques: sugar uptake measurements in rings of everted jejunum (micromol/D-fructose/ml cell water), transepithelial flux measurements in Ussing-type chambers (micromol D-fructose/cm2/h) and transport assays in preparation of brush border membrane vesicles (pmoles D-fructose/mg protein). Samples were taken from the bathing solution and from the extracts of the tissue for radioactivity counting.


RESULTS
Adding LPS (3 microg/ml) to tissue decreased the uptake and mucosal to serosal flux of 5 mM D-fructose across the enterocyte. LPS did not modify sugar uptake across brush border membrane vesicles. The inhibitory effect of LPS was suppressed by W-13 (5 x 10(-6) M), a Ca-calmodulin antagonist, and staurosporine (10(-7) and 10(-6) M) and GF-109203X (10(-6) M) a nonselective and selective protein kinase C (PKC) inhibitor respectively. Tumor Necrosis Factor (TNF-alpha), an immunoregulatory cytokine involved in septic responses occurring during bacterial infection at concentrations 3 x 10(-4) to 3 microg/ml, did not affect the sugar transport.


CONCLUSIONS
LPS can inhibit the intestinal uptake of D-fructose across the rabbit jejunum in vitro by intracellular processes related to PKC and calmodulin protein.
García-Herrera
J
J
Physiology Unit, Dept. of Pharmacology and Physiology, Veterinary Faculty, University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain.
Abad
B
B
Rodríguez-Yoldi
M J
MJ
D000818:Animals; D001834:Body Water / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000633:toxicity; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005632:Fructose / Q000378:metabolism*; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011817:Rabbits; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D002147:Calmodulin; D004731:Endotoxins; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D005632:Fructose; C044101:endotoxin, Escherichia coli; D011493:Protein Kinase C