Amelioration of Ischemia- and Reperfusion-Induced Myocardial Injury by 17β-Estradiol

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Abstract
Background 17β-Estradiol increases the production of nitric oxide (NO) and prostacyclin and opens Ca2+-activated K+ (KCa) channels. Whether these effects of 17β-estradiol reduce infarct size and the incidence of ventricular arrhythmia was investigated in dogs subjected to myocardial ischemia and reperfusion. Methods and Results Infarct size was measured in open-chest dogs after 90 minutes’ occlusion of the left anterior descending coronary artery and a subsequent 6 hours of reperfusion. Infusion of 17β-estradiol into the coronary artery was initiated 10 minutes before coronary occlusion and continued until after 1 hour of reperfusion, with the exception of the occlusion period. The difference in NO concentration between coronary venous and arterial blood 10 minutes after the onset of reperfusion was significantly greater in dogs treated with 17β-estradiol (10 ng · kg−1 · min−1) than in control animals. Infarct size (13.1±3.0% versus 43.7±5.4% of the area at risk) and the incidence of ventricular arrhythmi...