title: Immunohistochemical study on the distribution of sodium-dependent vitamin C transporters in the respiratory system of adult rat.
abstract: As vitamin C (L-ascorbic acid, VC) is known to be essential for many enzymatic reactions, the study on the transport mechanism of VC through cytoplasmic membrane is crucial to understanding physiological role of VC in cells and the respiratory system. In this regard, the study on the newly identified sodium-dependent VC transporters (SVCTs), SVCT1 and SVCT2, is required in organs that contain high concentration of VC. We have shown the distribution of SVCT proteins in the respiratory system, which has been reported to be one of the organs with a high concentration of VC, using immunohistochemical techniques. In the present study, intense SVCT immunoreactivities (IRs) were mainly localized in the respiratory system epithelial cells. In the trachea, both SVCT1 and 2 were localized in the psuedostratified ciliated columnar epithelium. In the terminal bronchiole, SVCT1 and 2 IRs were mainly observed in the apical portion of the simple columnar epithelium. In addition, SVCT IRs was localized within the cell membrane of some alveolar cells, even though we could not identify the exact cell types. These results provide the first evidence that intense SVCT1 and 2 IRs were found in the apical portion of the respiratory epithelial cells, suggesting that SVCT proteins in the apical portion could transport the reduced form of VC included in the airway surface liquid into the respiratory epithelial cells.
authors.affiliation: Department of Anatomy, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Shun Nu
authors.initials: SN
authors.lastname: Jin
authors.forename: Ga Hee
authors.initials: GH
authors.lastname: Mun
authors.forename: Ju Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Chang Seok
authors.initials: CS
authors.lastname: Oh
authors.forename: Jaehyup
authors.initials: J
authors.lastname: Kim
authors.forename: Yoon Hee
authors.initials: YH
authors.lastname: Chung
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Kang
authors.forename: Joong-Gon
authors.initials: JG
authors.lastname: Kim
authors.forename: Douk-Ho
authors.initials: DH
authors.lastname: Hwang
authors.forename: Young Il
authors.initials: YI
authors.lastname: Hwang
authors.forename: Dong Hoon
authors.initials: DH
authors.lastname: Shin
authors.forename: Wang Jae
authors.initials: WJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D001692:Biological Transport; D007150:Immunohistochemistry / Q000379:methods; D029363:Organic Anion Transporters, Sodium-Dependent / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012137:Respiratory System / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D060347:Sodium-Coupled Vitamin C Transporters; D027981:Symporters / Q000378:metabolism*; D014132:Trachea / Q000166:cytology
chemical_list: D029363:Organic Anion Transporters, Sodium-Dependent; C555166:Slc23a1 protein, rat; C555167:Slc23a2 protein, rat; D060347:Sodium-Coupled Vitamin C Transporters; D027981:Symporters; D012964:Sodium; D001205:Ascorbic Acid