Ang-(3-4) suppresses inhibition of renal plasma membrane calcium pump by Ang II.
Regul Pept
; 155(1-3): 81-90, 2009 Jun 05.
Article
em En
| MEDLINE
| ID: mdl-19345245
We previously demonstrated that Ang II inhibits the renal plasma membrane Ca(2+)-ATPase. In the present work we have studied the effect of Ang II, at concentrations similar to those found in the renal interstitium, on the Ca(2+)-ATPase from proximal tubule cells. High Ang II concentration (5 x 10(-7) mol/L) led to the recovery of Ca(2+)-ATPase activity previously inhibited by 50% at low Ang II concentration (10(-10) mol/L). Reactivation occurred in parallel with: (i) formation of only two dead-end metabolites [Ang-(3-4) and Tyr] after incubation of isolated membranes with micromolar Ang II; and (ii) dissociation of constitutive AT(1)R/AT(2)R heterodimers, which are preserved with 10(-10) mol/L Ang II. When the membranes were incubated with 10(-14) mol/L Ang-(3-4), inhibition by 10(-10) mol/L Ang II was no longer observed. The counteracting effect of Ang-(3-4) was abolished by PD123319, an antagonist of AT(2)R, and mimicked by CGP42112A, an agonist of AT(2)R. Ang-(1-7) is an intermediate in the formation of Ang-(3-4) via a pathway involving angiotensin-converting enzyme (ACE), and complete dipeptide breakdown to Tyr and Val is impaired by low Ang II. We conclude that Ang-(3-4) may be a physiological regulator of active Ca(2+) fluxes in renal proximal cells by acting within the renin-angiotensin axis.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fragmentos de Peptídeos
/
Angiotensina II
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Membrana Celular
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ATPases Transportadoras de Cálcio
/
Rim
Limite:
Animals
Idioma:
En
Revista:
Regul Pept
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Holanda