Estrogen diminishes postischemic hydroxyl radical production.
Reperfusion of blood flow to an ischemic myocardium is imperative to survival; ironically, it may also manifest several pathophysiological conditions. The most important of these are reperfusion arrhythmias and tissue injury and/or death. The mechanisms involved in reperfusion arrhythmias remain to be fully elucidated; however, increasing evidence indicates that reperfusion-induced arrhythmias are a free radical-mediated phenomenon. Acute administration of conjugated equine estrogen to dogs attenuates ischemia- and reperfusion-induced arrhythmias. The cardioprotective effect of estrogens in postmenopausal women is well documented, and recent studies suggest that estrogens possess strong antioxidant properties, with equine estrogens most potent. In this study we show that administration of conjugated equine estrogen to fully anesthetized dogs abolishes the burst of .OH radicals typically produced on reperfusion of the myocardium. This indicates that estrogen might attenuate reperfusion-induced ventricular arrhythmias by virtue of its antioxidant properties, suggesting a novel cardioprotective effect of the hormone.
McHugh
N A
NA
Division of Life Sciences, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8084, USA.
Merrill
G F
GF
Powell
S R
SR
D000818:Animals; D004285:Dogs; D004966:Estrogens, Conjugated (USP) / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005841:Gentisates; D062385:Hydroxybenzoates / Q000097:blood; D017665:Hydroxyl Radical / Q000378:metabolism*; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism*; D015425:Myocardial Reperfusion; D017682:Myocardial Stunning / Q000378:metabolism; D012737:Sex Factors
D004966:Estrogens, Conjugated (USP); D005841:Gentisates; D062385:Hydroxybenzoates; D017665:Hydroxyl Radical; C010925:2,5-dihydroxybenzoic acid