Abstract
Mesenteric arteries (230-290 μm) were isolated from virgin female rats at diestrous and proestrous phases of the estrous cycle and from ovariectomized (OVX) rats with or without estrogen (E2) replacement (17β-estradiol, 7.5 + 5 mg pellets, 21 d release). Arteries were mounted in a pressurized myograph system. Angiotensin-(1-7) [Ang-(1-7)] concentration-dependent responses (10-10-10-5 M) were determined in arteries preconstricted with endothelin-1 (10-7 M). Mesenteric arteries were pretreated with the specific Ang-(1-7) antagonist, D-[Ala7]-Ang-(1-7) (10-7 M) to assess the Ang-(1-7) receptor-mediated dilator effect. Ang-(1-7) did not dilate mesenteric arteries from virgin rats at diestrus and placebo-treated OVX female rats as compared to the time control; however, Ang-(1-7) elicited a modest dilation at proestrus as compared to diestrus, which reached statistical significance at 10-8 M concentrations. Ang-(1-7) caused a concentration-dependent vasodilation in mesenteric arteries of females with E2 replacement, with an EC 50 of 21 nM. D-[Ala7]-Ang-(1-7) blocked the vasodilator effect of Ang-(1-7). Our results demonstrate that during proestrus Ang-(1-7) elicits modest vasodilation as compared to diestrus, but lacks vasodilatory properties in vessels from diestrous and ovariectomized rats. Estrogen replacement restores a significant dilator response to Ang-(1-7) in OVX rats that is mediated by a D-[Ala7]-Ang-(1-7) sensitive site.
Original language | English (US) |
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Pages (from-to) | 161-165 |
Number of pages | 5 |
Journal | Endocrine |
Volume | 24 |
Issue number | 2 |
DOIs | |
State | Published - Jul 2004 |
Externally published | Yes |
Keywords
- Estrogen replacement
- Hypertension
- Renin-angiotensin system
- Vasodilation
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Endocrinology