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Tetrahydrobiopterin improves vascular endothelial function in ovariectomized rats
Kwok-Keung Lam1, Shung-Tai Ho, Mao-Hsiung Yen
1Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.
Journal of Biomedical Science
|March 27, 2002
Summary
Ovariectomized rats show impaired vascular response, possibly due to tetrahydrobiopterin (BH4) deficiency. Supplementing BH4 improved vasodilation, suggesting a therapeutic strategy for postmenopausal cardiovascular issues.
Area of Science:
- Cardiovascular Science
- Endocrinology
- Pharmacology
Background:
- Ovariectomy leads to decreased 17 beta-estradiol levels.
- Estrogen deficiency is linked to vascular dysfunction.
- Tetrahydrobiopterin (BH4) plays a role in vascular nitric oxide production.
Purpose of the Study:
- To investigate the role of tetrahydrobiopterin (BH4) in vascular responses of ovariectomized rats.
- To explore BH4 as a potential therapeutic agent for postmenopausal cardiovascular disorders.
Main Methods:
- Rats were divided into sham-operated and ovariectomized (Ovx) groups.
- Vascular reactivity was assessed using aortic rings.
- Plasma hormone levels, nitric oxide, superoxide anion production, and aortic BH4 content were measured.
Main Results:
- Ovx rats exhibited reduced vasodilator responses to acetylcholine and L-arginine compared to sham rats.
- Exogenous BH4 administration restored L-arginine-induced vasodilation in Ovx rats.
- Ovx rats showed increased superoxide anion production and decreased nitric oxide and BH4 levels in aortic tissue.
Conclusions:
- Ovariectomy impairs vascular reactivity in rats, potentially due to BH4 deficiency.
- BH4 supplementation may offer a novel therapeutic approach for cardiovascular complications associated with menopause.