Estradiol Induces Discordant Angiotensin and Blood Pressure Responses to Orthostasis in Healthy Postmenopausal Women
Bibliographic record
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.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".