Epithelial cells organic anions

OATP2B1 (old name OATP-B) is expressed at brush-border membranes of intestinal epithelial cells [32], OATP2B1 exhibited pH-sensitive transport activities for various organic anions such as estrone-3-sulfate, dehydroepiandros-terone sulfate, taurocholic acid, pravastatin, and fexofenadine [33], However, further studies are needed to determine the specific physiological and pharmacokinetic contribution of OATP2B1 for intestinal absorption of these compounds. 

Anthocyanins can be absorbed intact as glycosides (Figure 1.1). The mechanism of absorption is not known however, PassamontP found that anthocyanins can serve as ligands for bilitranslocase, an organic anion membrane carrier found in the epithelial cells of the gastric mucosa, and suggested that bilitranslocase could play a role in the bioavailability of anthocyanins. Table 1.3 presents a summary of the research that has demonstrated absorption of intact anthocyanins in the rat, pig or human. At least 13 different anthocyanins from 7 different food sources have been observed to be absorbed intact and to be present in plasma or urine (Table 1.3). In... 

The major important organic electrolytes and nonelectrolytes transported by epithelial cells include sugars, amino acids, nucleosides, organic cations, and organic anions. Transport systems have significant implications for the absorption, distribution, elimination, and pharmacokinetic properties of many clinically important drugs. The major epithelial tissues... 

Hori R, Okamura M,Takayama A, Hirozane K, and Takano M.Transport of organic anion in the OK kidney epithelial cell line. Am J Physiol 264 F975-980,1993. 

The Calu-3 human submucosal gland cell line forms polarized cell monolayers with tight junctions, produces mucus, and develops apical cilia when grown at an air interface. Transport studies can be performed after 10-14 days in culture, and it has been shown that Calu-3 cells express P-gp and actively transport amino acids, nucleosides, and dipeptide analogs organic anions, organic cations, polyamines, and efflux pump substrates are not actively transported.43,51,53-56 Because Calu-3 cells are not subject to the influence of multiple in vivo cell types, the expression of carrier proteins and enzymes may not reflect in vivo levels. Nevertheless, values obtained in Calu-3 permeability studies correlate well with those obtained from primary cultured rabbit tracheal epithelial cells and in vivo rat lung absorption studies.54 Mannitol permeation in Calu-3 cells is about 10 times less than that in vivo, but this is the same ratio difference between Caco-2 cells and in vivo intestinal epithelium.51... 

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