| Autor: |
KONISHI, Yutaka, HAGIWARA, Keiko, SHIMIZU, Makoto |
| Zdroj: |
Bioscience, Biotechnology, and Biochemistry; January 2002, Vol. 66 Issue: 11 p2449-2457, 9p |
| Abstrakt: |
Fluorescein is a marker-dye customary applied to the evaluation of tight-junctional permeability of epithelial cell monolayers. However, the true mechanism for the permeation has not been elucidated. Transepithelial transport of fluorescein in Caco-2 cell monolayers was therefore examined. Fluorescein transport was dependent on pH, and in a vectorical way in the apical-basolateral direction, but it was independent of the tight-junctional permeability of monolayers of these human intestinal cells. The permeation of fluorescein was concentration-dependent and saturable; the Michaelis constant was 7.7 mMand the maximum velocity was 40.3 nmol min−1(mg protein)−1. Benzoic acid competitively inhibited fluorescein transport, suggesting that fluorescein is transported by a monocarboxylic acid transporter (MCT). Antioxidative polyphenolic compounds such as ferulic acid from dietary sources, competitively inhibited the permeation of fluorescein. These compounds probably share a transport carrier with fluorescein. Measurement of the effects of phenolic acids on fluorescein transport across Caco-2 monolayers would be a useful way to evaluate the intestinal absorption or bioavailability of dietary phenolic acids. |
| Databáze: |
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