title: Differential distribution of the Sodium-vitamin C cotransporter-1 along the proximal tubule of the mouse and human kidney.
abstract: Vitamin C is reabsorbed from the renal lumen by one isoform of sodium-vitamin C co-transporters that mediate high affinity sodium-dependent L-ascorbic acid transport. Sodium-vitamin C cotransporter-1 mRNA has been detected in intestine and liver and the S3 segment of the renal proximal tubule. Here, we found that its distribution was broader and all three proximal tubule segments of mouse and human expressed the transporter but the S3 segment had the highest expression. Sodium-vitamin C co-transporter-1 expression was also found in the renal epithelial-derived LLC-PK1 cell line. Ascorbic acid transport in these cells was regulated by a single kinetic component that depended on the sodium concentration, pH and temperature. Reducing ascorbate concentration increased the apical expression of the transporter suggesting the presence of a feedback system for regulation of transporter abundance at the luminal membrane.
authors.affiliation: Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Tamara
authors.initials: T
authors.lastname: Castro
authors.forename: Marcela
authors.initials: M
authors.lastname: Low
authors.forename: Katterine
authors.initials: K
authors.lastname: Salazar
authors.forename: Hernán
authors.initials: H
authors.lastname: Montecinos
authors.forename: Manuel
authors.initials: M
authors.lastname: Cifuentes
authors.forename: Alejandro J
authors.initials: AJ
authors.lastname: Yáñez
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Slebe
authors.forename: Carlos D
authors.initials: CD
authors.lastname: Figueroa
authors.forename: Karin
authors.initials: K
authors.lastname: Reinicke
authors.forename: María
authors.initials: M
authors.lastname: de los Angeles García
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Henriquez
authors.forename: Francisco
authors.initials: F
authors.lastname: Nualart
mesh_terms: D000042:Absorption; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007422:Intestines / Q000737:chemistry; D007687:Kidney Tubules, Proximal / Q000737:chemistry; D007700:Kinetics; D008099:Liver / Q000737:chemistry; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D012964:Sodium / Q000378:metabolism*; D027981:Symporters / Q000378:metabolism*; D013696:Temperature
chemical_list: D012333:RNA, Messenger; D027981:Symporters; D012964:Sodium; D001205:Ascorbic Acid