The effect of estrogens on superoxide anion generation by human neutrophil granulocytes: Possible consequences of the antioxidant defense

The present study aimed to test whether, beyond the known antioxidant effect of estradiol, such a property is also possessed by estrone and estriol. For this purpose, an in vitro investigation of the effect of estrone and estriol on superoxide anion production by human neutrophil granulocytes was carried out. Blood samples were obtained from healthy volunteers and neutrophil granulocytes were separated for measurement of superoxide anion generation after incubation with estrone, estriol (10(-7), 10(-6) and 10(-5) M) and 17 ss-estradiol (10(-7) M). Superoxide anion production of isolated neutrophil granulocytes was quantified by photometry and using the reduction of ferricytochrome-C. When adding estrone and estriol to neutrophil granulocyte suspensions, the production of superoxide anion fell (10-5 M: 84.17 +/- 3.14% and 88.77 +/- 1.98% of control production, p < 0. 0 1 and p < 0. 05, respectively). Estradiol produced an antioxidant effect at lower concentration (10-7 M: 72.91 +/- 7.94% of control production, p < 0.001). The weak estrogens estrone and estriol, similarly to estradiol, are also able to reduce the superoxide anion release in our experimental model. This may have importance in the antioxiclant defense of biological systems.