目的　观察 17β -雌二醇对大鼠血管内皮细胞一氧化氮合酶 (NOS)活性的影响。 方法　用贴壁法和无酚红 164 0培养基培养大鼠血管内皮细胞 ,在 10nmol的 17β -雌二醇作用下 ,观察一定时间内内皮细胞的NOS活性。 结果　 10nmol的 17β -雌二醇作用 8～ 2 4hNOS活性显著增强 (同对照组相比 8hP <0 0 5 ;16h ,2 4hP <0 0 1)。 结论　 17β-雌二醇能增强大鼠血管内皮细胞的NOS活性 ,这可能是雌激素降低血管阻力、抑制动脉粥样硬化作用的重要机理之一 Objective To observe the effect of 17β - estradiol on the activity of nitric oxide synthase (NOS) in rat vascular endothelial cells. Methods Rat vascular endothelial cells were cultured with adherent method and without phenol red 164 0 medium. Under the action of 10 nmol of 17β - estradiol, the NOS activity of endothelial cells was observed. Results 10 nmol of 17β - estradiol enhanced the activity of NOS 8 ~ 24 hours (8hP <0 05; 16 h, 24 h P <0 01) compared with the control group. Conclusion 17β-estradiol can enhance the NOS activity of rat vascular endothelial cells, which may be one of the important mechanisms of estrogen lowering vascular resistance and inhibiting atherosclerosis