17β-Estradiol inhibits vascular smooth muscle cell proliferation and c-fos expression: role of nitric oxide

Rat vascular smooth muscle cells (VSMC) were used to study the effect of 17β estradiol (E 2) on cellular proliferation (cell counting), DNA synthesis ( 3 H thymidine incorporation) , MTT, c fos mRNA expression and nitric oxide (NO) release. The results obtained showed that E 2(10 -12 ～10 -8 mol/L) induced NO release from VSMC in a concentration dependent manner; 10 -8 mol/L E 2 significantly inhibited VSMC cellular proliferation and DNA synthesis induced by 10% FCS and 10 -7 mol/L ET 1, which was obviously reversed by 10 -7 mol/L tamoxifen and 10 -6 mol/L L NAME; after a pretreatment for 24 hours, 10 -8 mol/L E 2 significantly inhibited VSMC c fos mRNA expression induced by 10 -7 mol/L ET 1, which was also obviously reversed by 10 -6 mol/L L NAME . These results suggest that the inhibitory effects of E 2 on VSMC cellular proliferation and c fos mRNA expression are closely related with NO release in VSMC, which is, at least, partly medicated by ER .