FIG. 5.

Effects of ERα and ERβ agonists and antagonists on increases of total percentage change NOx levels (NO₂ and NO₃) in UAECs. Total NOx levels were quantified by the use of an HPLC-based assay. A) Basal percentage changes of NOx levels were 16%, 0.7%, and 9% at 10, 20, and 30 min, respectively. B) Elevations in UAECs NOx levels were observed with E₂β (10 and 100 nmol/L), PPT, ERα-specific agonist (1 nmol/L), DPN, ERβ-specific agonist (1 nmol/L), and ATP (100 nmol/L) across the 30-min time course. The basal NOx level was set to 0% to quantify the agonist-induced changes. C) UAECs were pretreated for 1 h with ICI 182,780 (ICI; 100 nmol/L); MPP, ERα-specific antagonist (100 nmol/L); PHTPP, ERβ-specific antagonist (100 nmol/L); or the combination of MPP + PHTPP (100 nmol/L +100 nmol/L), followed by E₂β treatment (10 nmol/L for 20 min). E₂β increased total NOx levels (65%) above control levels whereas ICI 182,780, MPP, or PHTPP alone had no effect. ICI 182,780 did not reduce the E₂β-induced increases in NOx levels. The antagonism of both ERs with MPP + PHTPP showed a decrease of basal NOx levels of −16%. E₂β treatment following MPP + PHTPP antagonists induced further decreases in NOx levels (−54%). λP < 0.05 vs. Cnt; *P < 0.05 vs. E₂β.