Abstract: Objective To explore the relationship of inhibitory proliferative ability induced by intracellular S-adenosylhomocysteine(SAH)accumulation and the expression of est rogen receptor(ER)in human umbilical vein endothelial cells.Methods I mmortalized HUVEC were treated without(normal)or with different concent rat ion 3-deazaadenosine (DZA),a potent S-adenosylhomocysteine hydrolase(SAHH)inhibitor,for 24,48 and 72h.The proliferative ability of HUVEC was measured with flow cytometry and TdT mediated dUTP nick ending labelling(TUNEL)methods.The ER protein and mRN A expression was analyzed with western blot and quantitative rev erse transcription-polymerase chainraction (qRT-PCR)respectively.The promoter methylation of ER gene was detected with methylation special PCR(M SP).Results The proliferative ability was decreased(mainly arrested at G₁/G₀ phase),and the apoptotic rate was increased after HUVEC treatment with DZA(P<0.05).The relative expression of ER mRNA and protein in HUVEC treated with DZA was lower than that of normal(P<0.05),but there was no changes of ER gene promotermethylation.Conclusion The inhibitory proliferative ability induced by intracellular SAH accumulation is correlative with ER expression,which not through altering promotermethy lation in HUVEC.