Glutathione Peroxidase-1 Plays a Major Role in Protecting Against Angiotensin II–Induced Vascular Dysfunction

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Abstract
Levels of reactive oxygen species, including hydrogen peroxide, increase in blood vessels during hypertension and in response to angiotensin II (Ang II). Although glutathione peroxidases are known to metabolize hydrogen peroxide, the role of glutathione peroxidase during hypertension is poorly defined. We tested the hypothesis that glutathione peroxidase-1 protects against Ang II–induced endothelial dysfunction. Responses of carotid arteries from Gpx1-deficient (Gpx1+/− and Gpx1−/−) and Gpx1 transgenic mice, and their respective littermate controls, were examined in vitro after overnight incubation with either vehicle or Ang II. Under control conditions, relaxation to acetylcholine (ACh; an endothelium-dependent agonist) was similar in control, Gpx1+/−, and Gpx1 transgenic mice, whereas in Gpx1−/− mice, responses to ACh were impaired. In control mice, ACh-induced vasorelaxation was not affected by 1 nmol/L of Ang II. In contrast, relaxation to ACh in arteries from Gpx1+/− mice was inhibited by ≈60% after ...