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Vasorelaxing effect of idoxifene on human internal mammary arteries

Wei Gengze, Yu Jun, Zhu Yunlong, Lin Shuxin, Kang Yunfan, Wang Rong, Zhou Jingjun, Zhang Qinghong

Department of Physiology,Fourth Military Medical University.Xi^an 710032,Shaanxi；China；Cardiovascular Surgery Center of Xijing Hospital,Fourth Military Medical University.Xi^an 710032,Shaanxi

Abstract

The results obtained from idoxifene were compared with those from 17#beta#-estradil (E_(2)). It was found that idoxifene caused a concentration-dependent relaxation of HIMA. The dose range was from 0.03 #mu#mol/L (minimal vasodilatory concentration) to 3 mmol/L (maximal vasodilatory concentration). It was also found that the vasorelaxation effect of idoxifene on HIMA was dependent on endothelium. E_(2) (0.1--100 #mu#mol/L) also resulted in an endothelium,-dependent vasorlaxation, but the vessels were 15-fold less sensitive to E_(2) than to idoxifene in their vasorelaxation responses. The EC_(50) for E_(2) was 4.65±0.34 #mu#mol/L, compared with 0.32±0.02 #mu#mol/L for idoxifene. The mean maximal vasodilatory value of E_(2) was 88.3±5.7%, compared with 88.6±7.2% for idoxifene. Pretreatment withi L-NAME (100 #mu#mol/L) abolished idoxifene-induced vasodilation virtually by blocking nitric oxide production. The vasorelaxing effect of idoxifene disappeared in the presnece of MB (10 #mu#mol/L). These findings demonstrate that idoxifene results in an endothelium-dependent vasorelaxation of HIMA, like estrogen. The effect of idoxifene is more potent than that of traditional estrogen, and is possibly mediated by NO-GC-cGMP pathway.

Key words: idoxifene;Estrogen;human internal mammary artery;Vasodilation

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Citing This Article：

Wei Gengze, Yu Jun, Zhu Yunlong, Lin Shuxin, Kang Yunfan, Wang Rong, Zhou Jingjun, Zhang Qinghong. Vasorelaxing effect of idoxifene on human internal mammary arteries. Acta Physiol Sin 2004; 56 (1): (in Chinese with English abstract).