Absorption of intact albumin across rat alveolar epithelial cell monolayers
| Autor: | Hiroshi Yamahara, Edward D. Crandall, Yasuhisa Matsukawa, Vincent H.L. Lee, Vijay K. Kalra, Kwang-Jin Kim |
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| Rok vydání: | 2003 |
| Předmět: |
Male
Pulmonary and Respiratory Medicine Physiology Absorption (skin) Biology chemistry.chemical_compound Physiology (medical) Electric Impedance medicine Animals Fluorescein Respiratory system Cells Cultured Serum Albumin Fluorescent Dyes Binding Sites Sodium Temperature Albumin Epithelial Cells Serum Albumin Bovine Cell Biology Epithelium In vitro Rats Specific Pathogen-Free Organisms Transport protein Pulmonary Alveoli Protein Transport medicine.anatomical_structure Biochemistry chemistry Biophysics Pulmonary alveolus Fluorescein-5-isothiocyanate Protein Binding |
| Zdroj: | American Journal of Physiology-Lung Cellular and Molecular Physiology. 284:L458-L465 |
| ISSN: | 1522-1504 1040-0605 |
| DOI: | 10.1152/ajplung.00237.2002 |
| Popis: | Transport characteristics of intact albumin were investigated using primary cultured rat alveolar epithelial cell monolayers. The apical-to-basolateral ( ab) flux of intact fluorescein isothiocyanate (FITC)-labeled albumin (F-Alb) is greater than basolateral-to-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 rate of ∼0.15 fmol · cm−2· s−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. |
| Databáze: | OpenAIRE |
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