125I-Angiotensin 1-7 binds to a different site than angiotensin 1-7 in tissue membrane preparations.
Endocrine
; 72(2): 529-538, 2021 05.
Article
em En
| MEDLINE
| ID: mdl-33415576
ABSTRACT
PURPOSE:
To study the receptor for Angiotensin (Ang) 1-7 using a radioligand (125I-Ang 1-7)-binding assay. For more than a decade, Mas has been viewed as the receptor for Ang 1-7; however, Ang 1-7 binding has not been pharmacologically characterized in tissue membrane preparations.METHODS:
Radioligand-binding assays were carried out using tissue membrane preparations using radioiodinated Angiotensin 1-7 (125I-Ang 1-7) to characterize its binding site. Non-radioactive 127I-Ang 1-7 was used to test if the addition of an iodine to the tyrosine4 moiety of Ang 1-7 changes the ability of Ang 1-7 to competitively inhibit 125I-Ang 1-7 binding.RESULTS:
125I-Ang 1-7 binds saturably, with moderately high affinity (10-20 nM) to a binding site in rat liver membranes that is displaceable by 127I-Ang 1-7 at nanomolar concentrations (IC50 = 62 nM) while Ang 1-7 displaces at micromolar concentrations (IC50 = 80 µM) at ~22 °C. This binding was also displaceable by inhibitors of metalloproteases at room temperature. This suggests that 125I-Ang 1-7 binds to MMPs and/or ADAMs as well as other liver membrane elements at ~ 22 °C. However, when 125I-Ang 1-7-binding assays were run at 0-4 °C, the same MMP inhibitors did not effectively compete for 125I-Ang 1-7.CONCLUSIONS:
The addition of an iodine molecule to the tyrosine in position 4 of Ang 1-7 drastically changes the binding characteristics of this peptide making it unsuitable for characterization of Ang 1-7 receptors.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Angiotensina II
/
Receptores de Angiotensina
Limite:
Animals
Idioma:
En
Revista:
Endocrine
Assunto da revista:
ENDOCRINOLOGIA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Estados Unidos