| Autor: |
Kwang-Jin Kim, Matsukawa, Yasuhisa, Yamahara, Hiroshi, Kalra, Vijay K., Lee, Vincent H.L., Crandall, Edward D. |
| Předmět: |
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| Zdroj: |
American Journal of Physiology: Lung Cellular & Molecular Physiology; Mar2003, Vol. 28 Issue 3, pL458, 8p, 1 Black and White Photograph, 11 Graphs |
| Abstrakt: |
Transport charaacteristics of intact albumin were investigated using primary cultured rat alveolar epithelial cell monolayers. The apicalto-basolateral (ab) flux of intact fluorescein isothiocyanate (FITC)-labeled albumin (F-Alb) is greater than basolateralto-apical (ba) flux at the same upstream [F-Alb] Net absorption of intact F-Alb occurs with half-maximal concentration of ∼1.6 μM and maximal transport rare of ∼0.15 fmol·cm[sup -2]·s[sup -1]. At 15 and 4°C, both ab and ba F-Alb fluxes are not different from zero, collapsing net absorption. The presence of excess unlabeled albumin (but not other macromolecule species) in either the apical or basolateral fluid significantly reduces both ab and ba unidirectional F-Alb fluxes. Photoaffinity labeling of apical cell membranes revealed an ∼60-kDa protein that exhibits specificity for albumin. These data indicate that net absorption of intact albumin takes place via saturable receptor-mediated transcellular endocytotic processes recognizing albumin, but not other macromolecules, that may play an important role in alveolar homeostasis in the mammalian lung. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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