title: Na-P(i) cotransport sites in proximal tubule and collecting tubule of winter flounder (Pleuronectes americanus).
abstract: Localization of a recently described and cloned Na-Pi cotransport system from flounder was investigated by reverse transcription-polymerase chain reaction (RT-PCR) of microdissected tubules and by immunocytochemistry of kidney of winter flounder. Histological examination showed a small glomerulus, an extremely short proximal tubule PI with a selective affinity to Lens culinaris agglutinin from lentils, and an extensive second proximal tubule segment PII (> 90% of proximal tubules), consisting of cells with numerous apical clear vesicles and extensive amplification of basolateral cell membranes. PII merged with the collecting tubule/ collecting duct (CT/CD) system without a distal segment. By RT-PCR, PII cells revealed high levels of NaPi-II related RNA; low levels were also observed in CTs. Previously characterized antisera against different epitopes of flounder NaPi-II specifically labeled the basolateral regions of PII and the apical cell portion of CT/CD cells and of some PII cells. These results suggest that tubular secretion of P(i) occurs in PII of teleost fish with modulation of urinary P(i) content in the subsequent CT/CD system.
authors.affiliation: Institut für Anatomie und Zellbiologie I, Universität Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Elger
authors.forename: A
authors.initials: A
authors.lastname: Werner
authors.forename: P
authors.initials: P
authors.lastname: Herter
authors.forename: B
authors.initials: B
authors.lastname: Kohl
authors.forename: R K
authors.initials: RK
authors.lastname: Kinne
authors.forename: H
authors.initials: H
authors.lastname: Hentschel
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D005432:Flounder; D007150:Immunohistochemistry; D007685:Kidney Tubules, Collecting / Q000737:chemistry*; D007687:Kidney Tubules, Proximal / Q000737:chemistry*; D037102:Lectins / Q000378:metabolism; D008297:Male; D008854:Microscopy, Electron; D037121:Plant Lectins; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012194:RNA-Directed DNA Polymerase; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters
chemical_list: D002352:Carrier Proteins; D037102:Lectins; D037121:Plant Lectins; D012333:RNA, Messenger; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; C033619:lentil lectin; D012194:RNA-Directed DNA Polymerase