Mineralocorticoid effects in the kidney: correlation between alphaENaC, GILZ, and Sgk-1 mRNA expression and urinary excretion of Na+ and K+.

Details

Serval ID
serval:BIB_D994A387AF2D
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Mineralocorticoid effects in the kidney: correlation between alphaENaC, GILZ, and Sgk-1 mRNA expression and urinary excretion of Na+ and K+.
Journal
Journal of the American Society of Nephrology
Author(s)
Muller O.G., Parnova R.G., Centeno G., Rossier B.C., Firsov D., Horisberger J.D.
ISSN
1046-6673 (Print)
ISSN-L
1046-6673
Publication state
Published
Issued date
2003
Volume
14
Number
5
Pages
1107-1115
Language
english
Abstract
Aldosterone exerts its effects through interactions with two types of binding sites, the mineralocorticoid (MR) and the glucocorticoid (GR) receptors. Although both receptors are known to be involved in the anti-natriuretic response to aldosterone, the mechanisms of signal transduction leading to modulation of electrolyte transport are not yet fully understood. This study measured the Na(+) and K(+) urinary excretion and the mRNA levels of three known aldosterone-induced transcripts, the serum and glucocorticoid-induced kinase (Sgk-1), the alpha subunit of the epithelial Na(+) channel (alphaENaC), and the glucocorticoid-induced-leucine-zipper protein (GILZ) in the whole kidney and in isolated cortical collecting tubules of adrenalectomized rats treated with low doses of aldosterone and/or dexamethasone. The resulting plasma concentrations of both steroids were close to 1 nmol/L. Aldosterone, given with or without dexamethasone, induced anti-natriuresis and kaliuresis, whereas dexamethasone alone did not. GILZ and alphaENaC transcripts were higher after treatment with either or both hormones, whereas the mRNA abundance of Sgk-1 was increased in the cortical collecting tubule by aldosterone but not by dexamethasone. We conclude the increased expression of Sgk-1 in the cortical collecting tubules is a primary event in the early antinatriuretic and kaliuretic responses to physiologic concentrations of aldosterone. Induction of alphaENaC and/or GILZ mRNAs may play a permissive role in the enhancement of the early and/or late responses; these effects may be necessary for a full response but do not by themselves promote early changes in urinary Na(+) and K(+) excretion.
Keywords
Aldosterone/blood, Aldosterone/pharmacology, Animals, Dexamethasone/blood, Dexamethasone/pharmacology, Epithelial Sodium Channel, Gene Expression/drug effects, Gene Expression/physiology, Glucocorticoids/blood, Glucocorticoids/pharmacology, Immediate-Early Proteins, Kidney Cortex/drug effects, Kidney Cortex/metabolism, Kidney Tubules, Collecting/drug effects, Kidney Tubules, Collecting/metabolism, Male, Nuclear Proteins, Potassium/urine, Protein-Serine-Threonine Kinases/genetics, Protein-Serine-Threonine Kinases/metabolism, RNA, Messenger/analysis, Rats, Rats, Wistar, Sodium/urine, Sodium Channels/genetics, Sodium Channels/metabolism, Transcription Factors/genetics, Transcription Factors/metabolism
Pubmed
Web of science
Open Access
Yes
Create date
24/01/2008 12:32
Last modification date
20/08/2019 15:58
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