AJP - Cell Physiology, Vol 263, Issue 4 C810-C817, Copyright © 1992 by American Physiological Society
Adrenalectomy reduces alpha 1 and not beta 1 Na(+)-K(+)-ATPase mRNA expression in rat distal nephron
N. Farman, N. Coutry, N. Logvinenko, M. Blot-Chabaud, R. Bourbouze and J. P. Bonvalet
Institut National de la Sante et de la Recherche Medicale U. 246, Unite d'Enseignement et de Recherche Xavier Bichat, Paris, France.
The abundance of mRNA of alpha 1-, alpha 2-, alpha 3-, beta 1-, and beta
2-isoforms of Na(+)-K(+)-ATPase was examined in several renal structures of
normal and adrenalectomized (ADX) rats. In situ hybridization with
35S-labeled cRNA probes was performed on kidney sections from adult rats.
The number of silver grains per unit surface area was quantified over cells
of the glomerulus, proximal convoluted tubules (PCT), early distal tubules
(EDT), and cortical collecting ducts (CCD). In normal rat kidney, alpha 1-
and beta 1-mRNA was detected in PCT, EDT, and CCD, with the following range
of magnitude: EDT > CCD > PCT > glomerulus. The amount of alpha 1-
and beta 1-mRNA was equivalent. A large abundance of these two mRNA species
was also found in the medullary thick ascending limb of the loop of Henle.
Expression of alpha 2, alpha 3, and beta 2 was very low and evenly
distributed over any cell type. In ADX, a significant decrease in alpha
1-mRNA (30%) was observed in EDT and CCD, with no change in PCT. beta
1-mRNA abundance was unaffected by adrenalectomy. These results indicate
that 1) in the rat kidney alpha 1- and beta 1-mRNA are coexpressed at a
similar level that varies along the renal tubule according to the cell
type, 2) minute expression of alpha 2-, alpha 3-, and beta 2-mRNA is
present in the kidney, and 3) corticosteroid depletion reduces the
expression of alpha 1- and not beta 1-mRNA in the corticosteroid-sensitive
tubular cells.
