Aldosterone induces rapid apical translocation of ENaC in early portion of renal collecting system: possible role of SGK

Détails

ID Serval
serval:BIB_7F99A1948989
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Aldosterone induces rapid apical translocation of ENaC in early portion of renal collecting system: possible role of SGK
Périodique
American Journal of Physiology. Renal Physiology
Auteur(s)
Loffing  J., Zecevic  M., Feraille  E., Kaissling  B., Asher  C., Rossier  B. C., Firestone  G. L., Pearce  D., Verrey  F.
ISSN
0363-6127
Statut éditorial
Publié
Date de publication
04/2001
Peer-reviewed
Oui
Volume
280
Numéro
4
Pages
F675-82
Notes
In Vitro
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Apr
Résumé
Aldosterone controls sodium reabsorption and potassium secretion in the aldosterone-sensitive distal nephron (ASDN). Although clearance measurements have shown that aldosterone induces these transports within 30--60 min, no early effects have been demonstrated in vivo at the level of the apical epithelial sodium channel (ENaC), the main effector of this regulation. Here we show by real-time RT-PCR and immunofluorescence that an aldosterone injection in adrenalectomized rats induces alpha-ENaC subunit expression along the entire ASDN within 2 h, whereas beta- and gamma-ENaC are constitutively expressed. In the proximal ASDN portions only, ENaC is shifted toward the apical cellular pole and the apical plasma membrane within 2 and 4 h, respectively. To address the question of whether the early aldosterone-induced serum and glucocorticoid-regulated kinase (SGK) might mediate this apical shift of ENaC, we analyzed SGK induction in vivo. Two hours after aldosterone, SGK was highly induced in all segment-specific cells of the ASDN, and its level decreased thereafter. In Xenopus laevis oocytes, SGK induced ENaC activation and surface expression by a kinase activity-dependent mechanism. In conclusion, the rapid in vivo accumulation of SGK and alpha-ENaC after aldosterone injection takes place along the entire ASDN, whereas the translocation of alpha,beta,gamma-ENaC to the apical plasma membrane is restricted to its proximal portions. Results from oocyte experiments suggest the hypothesis that a localized activation of SGK may play a role in the mediation of ENaC translocation.
Mots-clé
Aldosterone/*pharmacology Animals Biological Transport/drug effects/physiology Cell Membrane/metabolism Cell Polarity/physiology Epithelial Sodium Channel Gene Expression/drug effects/physiology Immediate-Early Proteins Kidney Tubules, Collecting/drug effects/*enzymology Male *Nuclear Proteins Oocytes/physiology Patch-Clamp Techniques Protein-Serine-Threonine Kinases/genetics/*metabolism RNA, Messenger/analysis Rats Rats, Wistar Sodium/metabolism Sodium Channels/genetics/*metabolism Xenopus laevis
Pubmed
Web of science
Création de la notice
24/01/2008 14:00
Dernière modification de la notice
03/03/2018 18:43
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