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Estradiol induces discordant angiotensin and blood pressure responses to orthostasis in healthy postmenopausal women.
- Source :
-
Hypertension (Dallas, Tex. : 1979) [Hypertension] 2005 Mar; Vol. 45 (3), pp. 399-405. Date of Electronic Publication: 2005 Feb 07. - Publication Year :
- 2005
-
Abstract
- Postmenopausal estrogen replacement therapy (ERT) is reported to increase angiotensin II under resting conditions. To determine the implications of this increase for cardiovascular regulation during simulated orthostasis, blood pressure (BP), heart rate (HR), renin, angiotensinogen, angiotensin II, and aldosterone were measured at rest and during lower body negative pressure (LBNP; -10, -20, and -40 mm Hg). We studied 13 normotensive postmenopausal women (54+/-2 [mean+/-SE] years) before and after 1 month of oral estradiol 2 mg daily, and 14 premenopausal women. LBNP activated the renin-angiotensin system acutely in premenopausal but not postmenopausal women. Resting renin and aldosterone were unaffected by estradiol, whereas angiotensinogen (P<0.001) and angiotensin II (P<0.01) increased. Renin, aldosterone, and HR responses to LBNP (which tended to be less in postmenopausal women [P=0.06]) were not affected by estradiol. Importantly, angiotensin II was higher on estradiol during all stages of LBNP, and increased 70% above resting values at the end of this stimulus (P<0.05), yet BP was significantly lower, both at rest (P<0.05) and during LBNP (P<0.01). In summary, in normotensive postmenopausal women, estradiol increases angiotensin II, but not aldosterone, at rest and during orthostatic stress, yet lowers, rather than raises, BP under both conditions. Downregulation of vascular and adrenal responsiveness to angiotensin II may protect healthy women against this activation. Loss of such protection may elevate BP and have adverse implications for women with conditions that impair their capacity to counteract the pathological actions of angiotensin II. This may contribute to higher cardiovascular event rates reported in recent ERT trials.
- Subjects :
- Aldosterone blood
Angiotensinogen blood
Case-Control Studies
Female
Hemodynamics
Humans
Lower Body Negative Pressure
Middle Aged
Renin blood
Renin-Angiotensin System
Angiotensin II blood
Blood Pressure drug effects
Blood Pressure physiology
Estradiol adverse effects
Postmenopause
Posture physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1524-4563
- Volume :
- 45
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Hypertension (Dallas, Tex. : 1979)
- Publication Type :
- Academic Journal
- Accession number :
- 15699442
- Full Text :
- https://doi.org/10.1161/01.HYP.0000157161.78721.5c