Aldosterone stimulates active Na+ transport in rabbit urinary bladder by both genomic and non-genomic processes.
Eur J Pharmacol
; 510(3): 181-6, 2005 Mar 14.
Article
em En
| MEDLINE
| ID: mdl-15763241
The ability of aldosterone to stimulate Na+ transport in a range of epithelial tissues has been known for many years. Early work suggested that aldosterone had a delayed action operating by transcriptional up-regulation of proteins such as the epithelial Na+ channel. However more recent data has suggested that the hormone has a short-term non-genomic action. In this paper we investigate short and long-term actions of aldosterone on Na+ transport in the rabbit urinary bladder. We have shown that aldosterone stimulates epithelial Na+ channel activity, as measured by the amiloride-sensitive short-circuit current over a 3.75 h period and that this action is potentiated by cAMP. Using reverse transcriptase-polymerase chain reaction we have shown that aldosterone and forskolin in combination up-regulate mRNA synthesis for the beta- and gamma-subunits of the epithelial Na+ channel. Using Western blotting we have shown in the case of the beta-subunit that a corresponding increase in channel protein occurs. We have also demonstrated that aldosterone in the presence of inhibitors of phosphodiesterase can stimulate the short-circuit current across rabbit bladder epithelium over a 20 min period. An explanation for the synergistic interaction between aldosterone and cAMP is provided. We have shown that aldosterone can increase cAMP levels within urothelial cells over a 4 min period. We propose that this represents a non-genomic action of the steroid hormone.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sódio
/
Bexiga Urinária
/
Canais de Sódio
/
Aldosterona
Limite:
Animals
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article