Inhibitory Effect of Estrogens on the Oxidative Hemolysis Induced by 2-Amidinopropane Hydrochloride, a Free Radical Generator

<P>We investigated the effect of estrogens, 17 beta-estradiol, estradiol-3-benzoate and estrone, on 2-amidinopropane hydrochloride (AAPH)-provoked, free radical-dependent hemolysis in vitro. Incubation experiment was performed by mixing AAPH (400 mM) and washed human erythrocyte suspension with or without various sex hormones and radical scavengers. After 170 min of incubation, 50% hemolysis was detected in the control group (incubation without sex hormones or radical scavengers), whereas after the addition of estrogens (5 mM), hemolysis was nearly completely inhibited until 180 min of incubation. It was found that the inhibitory activities of estrogens on oxidative hemolysis were stronger than that of alpha-tocopherol and had nearly identical to that of N-acetyl-L-cysteine. Testosterone had no inhibitory effects. The elevation of thiobarbituric acid-reactive substances, a marker for lipid peroxidation, was also inhibited by estrogens. These results add further evidence that estrogens are strong radical scavengers in humans.</P>