Data/hora: 06/06/2024 01:17:32

Provedor de dados: | 56
País: | Brazil
Título: | Bi-directional actions of estrogen on the renin-angiotensin system
Autores: | Brosnihan,K.B.; Senanayake,P.S.; Li,P.; Ferrario,C.M.
Data: | 1999-04-01
Ano: | 1999
Palavras-chave: | Renin; Angiotensin converting enzyme; Angiotensin peptides; Angiotensin receptors; Bradykinin; Nitric oxide; Kinins; Vasodilation; Hormone replacement.
Resumo: | Estrogen stimulates the renin-angiotensin system by augmenting both tissue and circulating levels of angiotensinogen and renin. We show, however, that angiotensin converting enzyme (ACE) activity in the circulation and in tissues is reduced in two animal models of postmenopausal chronic hormone replacement. We observed a reduction of ACE activity in association with a significant increase in plasma angiotensin I (Ang I) and hyperreninemia in ovariectomized monkeys treated with Premarin (conjugated equine estrogen) replacement for 30 months. Plasma angiotensin II (Ang II) levels were not increased in monkeys treated with estrogen, suggesting that the decrease in ACE curtailed the formation of the peptide. The Ang II/Ang I ratio, an in vivo index of ACE activity, was significantly reduced by estrogen treatment, further supporting the biochemical significance of estrogen's inhibition of ACE. In ovariectomized transgenic hypertensive (mRen2)27 rats submitted to estrogen replacement treatment for 3 weeks, ACE activity in plasma and tissue (aorta and kidney) and circulating Ang II levels were reduced, whereas circulating levels of angiotensin-(1-7) (Ang-(1-7) were increased. Ang-(1-7), the N-terminal fragment of Ang II, is a novel vasodilator and antihypertensive peptide. Thus, the net balance of these effects of estrogen on the renin-angiotensin vasoconstrictor/vasodilator system is to promote the antihypertensive effect.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999000400001
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X1999000400001
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.32 n.4 1999
Fonte: | info:eu-repo/semantics/openAccess