Non coordinate regulation of epithelial sodium channel and na, k
-atpase subunit mrnas in kidney and colon by aldosterone.
Escoubet, Brigitte, Christiane Coureau, Jean-Pierre Bonvalet, and
Nicolette Farman.
Institut F[acute]ed[acute]eratif de Recherche Cellules
Epith[acute]eliales, INSERM U 426, and U 246, and D[acute]epartement
de Physiologie, Facult[acute]e de M[acute]edecine X. Bichat,
Universit[acute]e Paris 7, Paris France.
APStracts 3:0381C, 1996.
Distal colon and renal cortical collecting ducts are major effectors
of aldosterone-dependent sodium homeostasis. Sodium is absorbed by
entry through an apical amiloride-sensitive sodium channel and
extruded by Na,K-ATPase at the basolateral membrane. Using RNase
protection assay, we studied, in vivo, aldosterone regulation of a,
b, and g subunit of the epithelial sodium channel (rENaC) and a1 and
b1 subunit of the Na,K-ATPase. In the kidney, Na,K-ATPase mRNAs were
also assayed over discrete tubular segments by in situ hybridization.
In rat colon, all three rENaC mRNAs were decreased by adrenalectomy
with major effect on b and [gamma] and were restored with 7 day
aldosterone-treatment, not with 2 day treatment, whereas, in kidney,
only [alpha] transcripts varied. Na,K-ATPase a1 and b1 subunit mRNAs
in both organs were not (b1) or mildly (a1) affected after
adrenalectomy.
Received 22 July 1996; accepted in final form 19 November 1996.
APS Manuscript Number C405-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996