Fig. 3.
Estrogen stimulation of NO release by 17β-estradiol and E2-BSA and its antagonism by tamoxifen.
17β-Estradiol (17 B-E; 10−9 mol/L) stimulates NO release from granulocytes within 2 minutes of its application. The release of NO is stimulated by 17β-estradiol coupled to 10−9 mol/L BSA (E2-BSA) with the same kinetic profile as 17β-estradiol (P < .01), which indicates that estradiol acts at the membrane surface. The NO release stimulated by 17β-estradiol and E2-BSA was antagonized by tamoxifen (Tam), an antiestrogen. We added 17β-estradiol and E2-BSA to the milieu at 2 minutes, whereas 10−9 mol/L tamoxifen was added at 0 minutes. Each experiment was repeated 4 times, and the resulting mean value plus or minus SEM was graphed.