What question did this study set out to answer?

To determine whether estrogen moderates arteriolar dysfunction in female spontaneously hypertensive rats by preserving vascular nitric oxide synthesis.

June 1, 1997Hypertension

Estrogen Maintains Nitric Oxide Synthesis in Arterioles of Female Hypertensive Rats

Q: What is the clinical evidence from this study?

Study design: Other. Population: Spontaneously hypertensive rats (SHR). Intervention: Estrogen replacement (17 beta-estradiol benzoate) vs. Ovariectomized females (fSHR-OV), males (mSHR), intact females (fSHR). Primary outcome: Arteriolar diameter changes in response to pressure and vasodilators.

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Key result

Estrogen replacement in ovariectomized spontaneously hypertensive rats preserved nitric oxide synthesis in skeletal muscle arterioles, maintaining nitric oxide-mediated dilations.

Population

12-week-old spontaneously hypertensive rats, isolated gracilis muscle arterioles

Comparison

Estrogen replacement in ovariectomized female SHR vs Ovariectomized female SHR without estrogen…

Design

Preclinical

Authors

AHAn HuangFirst Affiliated Hospital of Jiangxi Medical College DSDong SunShanxi Medical University GKGabor KaleySemmelweis University

Discussion

Member takes

Implication

Should not inform estrogen use in hypertensive women; leaves open translation of NO preservation to human resistance vessels.

Key Points

To determine whether estrogen moderates arteriolar dysfunction in female spontaneously hypertensive rats by preserving vascular nitric oxide synthesis.
Isolated gracilis muscle arterioles (~55 µm diameter) from 12-week-old spontaneously hypertensive rats across four cohorts: intact females (fSHR), ovariectomized females (fSHR-OV), ovariectomized females with 17β-estradiol replacement (fSHR-OV+ES), and males (mSHR).
Evaluated arteriolar diameter under perfusion pressures ranging from 60 to 120 mm Hg and measured luminal diameter changes in response to substance P, sodium nitroprusside, the calcium ionophore A23187, and the nitric oxide synthase inhibitor Nω-nitro-L-arginine (L-NNA).
Pressure-induced arteriolar diameter in mSHR and fSHR-OV was significantly reduced by approximately 10% compared to fSHR and fSHR-OV+ES, and L-NNA decreased basal diameter in fSHR (~19%) and fSHR-OV+ES (~17%), abolishing tone differences between groups.
Arteriolar dilation to substance P (5 × 10⁻⁸ mol/L) was 140% greater in fSHR and fSHR-OV+ES than in mSHR and fSHR-OV, whereas dilation to sodium nitroprusside was equivalent across all cohorts.
A23187 elicited vasodilation in fSHR (5.9 ± 1.5% to 19.2 ± 2.1%) and fSHR-OV+ES (4.3 ± 1.0% to 15.0 ± 4.0%), but produced paradoxical vasoconstriction in mSHR (-7.5 ± 1.6% to -36.9 ± 4.1%) and fSHR-OV (-2.6 ± 1.7% to -11.5 ± 6.1%).

Structured PICO

Population

12-week-old spontaneously hypertensive rats (SHR), isolated gracilis muscle arterioles (approximately 55 microns in diameter)

Intervention

Estrogen replacement (17 beta-estradiol benzoate 50 micrograms/kg SC every 48 hours) in ovariectomized female SHR

Comparator

Ovariectomized female SHR without estrogen replacement, intact female SHR, and male SHR

Outcome

Arteriolar diameter changes in response to perfusion pressures (60, 80, 100, and 120 mm Hg) and various concentrations of substance P, sodium nitroprusside, and A23187surrogate

Estrogen preserves nitric oxide synthesis in skeletal muscle arterioles of female spontaneously hypertensive rats, modulating pressure-induced myogenic tone and maintaining NO-mediated dilations.

Cite This Study

Huang et al. (1997) studied Spontaneously hypertensive rats (SHR). Estrogen replacement (17 beta-estradiol benzoate) vs. Ovariectomized females (fSHR-OV), males (mSHR), intact females (fSHR) was evaluated on Arteriolar diameter changes in response to pressure and vasodilators. Estrogen replacement in ovariectomized spontaneously hypertensive rats preserved nitric oxide synthesis in skeletal muscle arterioles, maintaining nitric oxide-mediated dilations.

synapsesocial.com/papers/6a092c6fc64d0aaf94b622db https://doi.org/10.1161/01.hyp.29.6.1351

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Estrogen Maintains Nitric Oxide Synthesis in Arterioles of Female Hypertensive Rats

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Estrogen Maintains Nitric Oxide Synthesis in Arterioles of Female Hypertensive Rats

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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