Carnitine Absorption: Effects of Sodium Valproate and Sodium Octanoate in the Caco-2 Cell Culture Model of Human Intestinal Epithelium
The Caco-2 cell culture system was used as a model to investigate the mechanism of carnitine absorption in human small intestinal epithelium, and to determine if valproic acid inhibits this process in the model system. The hypotheses tested were: Carnitine is absorbed by a mechanism not involving ca...
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Published in | The Journal of nutritional biochemistry Vol. 9; no. 4; pp. 228 - 235 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
New York, NY
Elsevier Inc
01.04.1998
Elsevier Science |
Subjects | |
Online Access | Get full text |
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Summary: | The Caco-2 cell culture system was used as a model to investigate the mechanism of carnitine absorption in human small intestinal epithelium, and to determine if valproic acid inhibits this process in the model system. The hypotheses tested were: Carnitine is absorbed by a mechanism not involving carrier-mediated transport; and valproic acid specifically inhibits carnitine absorption. Results of the investigation were consistent with exclusively passive, paracellular absorption of carnitine across the Caco-2 cell monolayer. Saturable and structure-specific intracellular accumulation of carnitine from the apical medium was observed, but was independent of the process of absorption. At high concentration (10 mmol/L), both sodium valproate and its straight-chain analog sodium octanoate inhibited cellular accumulation of carnitine from the apical medium, but enhanced transmonolayer passage of carnitine from the apical to the basal medium. Lower concentrations of these organic acid salts (0.1 or 1 mmol/L) did not affect cellular accumulation of carnitine, but at 1 mmol/L concentration, they slightly enhanced transmonolayer flux. Paradoxically, cells cultured for 5 days in the presence of sodium valproate or sodium octanoate accumulated carnitine at a faster rate than cells cultured in the absence of these compounds. It is concluded that carnitine is absorbed across the Caco-2 monolayer by a passive, paracellular route that is not inhibited by sodium valproate. |
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Bibliography: | S20 1997091806 S30 |
ISSN: | 0955-2863 1873-4847 |
DOI: | 10.1016/S0955-2863(98)00004-7 |