[Effect of inhibition by 17beta-estradiol on endothelin-induced proliferation of vascular smooth muscle cells].

AIM AND METHODS

To determine the effect of 17 beta-estradiol on proliferation of cultured vascular smooth muscle cells (VSMC) and expression of ET(A) receptor mRNA stimulated by endothelin-1 (ET-1). The experimental models of proliferation in cultured rat aortic smooth muscle cells induced by ET-1 was established. The 3H-thymidine ([3H]-TdR) incorporation, cell counts and reverse transcription-polymerase chain reaction (RT-PCR) were used in this study.

RESULTS

BQ123, the selective ET(A) receptor antagonist, inhibited the increase of [3H]-TdR incorporation and cell number in response to ET-1 of VSMC.17 beta-estradiol may reverse the increase of [3H] TdR incorporation and cell number stimulated by ET-1. 17 beta-estradiol downregulated of ET(A) receptor mRNA expression, with the maximum at 12 hours, which was partially prevented by tamoxifen, an estrogen receptor antagonist.

CONCLUSION

The proliferation of VSMC stimulated by ET-1 was mainly through ET(A) receptor. 17 beta-estradiol inhibited the proliferation of VSMC stimulated by ET-1, which might be through downregulation of ET(A) receptor.