Angiotensin-(1-7) modulates the ouabain-insensitive Na+-ATPase activity from basolateral membrane of the proximal tubule.
Biochim Biophys Acta
; 1467(1): 189-97, 2000 Jul 31.
Article
en En
| MEDLINE
| ID: mdl-10930521
Angiotensin-(1-7) (Ang-(1-7)) modulates the Na+-ATPase, but not the Na+,K+-ATPase activity present in pig kidney proximal tubules. The Na+-ATPase, insensitive to ouabain, but sensitive to furosemide, is stimulated by Ang-(1-7) (68% by 10(-9) M), in a dose-dependent manner. This effect is due to an increase in Vmax, while the apparent affinity of the enzyme for Na+ is not modified. Saralasin, a general angiotensin receptor antagonist, abolishes the stimulation, demonstrating that the Ang-(1-7) effect is mediated by receptor. The Ang-(1-7) stimulatory effect is not changed by either PD 123319, an AT2 receptor antagonist, or A779, an Ang-(1-7) receptor antagonist. On the other hand, increasing the concentration of the AT1 receptor antagonist losartan from 10(-11) to 10(-9) M, reverses the Ang(1-7) stimulation completely. A further increase to 10(-3) M losartan reverses the Na+-ATPase activity to a level similar to that obtained with Ang-(1-7) (10(-9) M) alone. The stimulatory effect of Ang-(1-7) at 10(-9) M is similar to the effect of angiotensin II (AG II) alone. However, when the two peptides are both present, Na+-ATPase activity is restored to control values. These data suggest that Ang-(1-7) selectively modulates the Na+-ATPase activity present in basolateral membranes of kidney proximal tubules through a losartan-sensitive receptor. This receptor is probably different from the receptor involved in the stimulation of the Na+-ATPase activity by angiotensin II.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fragmentos de Péptidos
/
Angiotensina I
/
Adenosina Trifosfatasas
/
Proteínas de Transporte de Catión
/
Túbulos Renales Proximales
Límite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
2000
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Países Bajos