Evidence for a novel angiotensin II receptor involved in angiogenesis in chick embryo chorioallantoic membrane.
Am J Physiol
; 264(2 Pt 2): R460-5, 1993 Feb.
Article
en En
| MEDLINE
| ID: mdl-8447504
Angiotensin II acts as a growth factor in the cardiovascular system and has been implicated in angiogenesis. The existence of at least two types of angiotensin II receptors, the AT1 and the AT2 receptors, has been suggested by ligand binding studies. We used three different AT receptor antagonists to study the receptor mediating angiotensin II-induced angiogenesis in the chorioallantoic membrane (CAM) of the chick embryo. Angiotensin II caused pronounced angiogenesis of pre- and postcapillary vessels of 30-40%. This response could only be blocked by adding the peptidergic AT2 antagonist CGP-42112A. The nonpeptidergic AT2 antagonist PD123319 and AT1 antagonist losartan (DuP 753) were not effective. In addition, we used radioligand binding studies with a range of ligands to define the nature of the receptor. Our results show a high density of specific single class AT receptor with a total number of binding sites of 1,190 fmol/mg protein and an affinity constant for angiotensin II of 2.7 nM. The inhibitory concentrations (IC50) for CGP-42112A, PD 123319 and losartan were 724, > 100,000, and 59,000 nM, respectively. Our studies suggest that these binding sites act as receptors for angiotensin II-induced angiogenesis. Both functional and radioligand binding studies suggest that the receptor is different from the classical mammalian AT1 and AT2 receptors.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Vasos Sanguíneos
/
Receptores de Angiotensina
/
Corion
/
Alantoides
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Am J Physiol
Año:
1993
Tipo del documento:
Article
País de afiliación:
Países Bajos
Pais de publicación:
Estados Unidos