Abstract: Objective:This study was designed to research the effects of daidzein on bone calcium metabolism in ovariectomized rats.Methods:Forty 90-day old female Sprague Dawley rats were randomly divided into four groups.10 rats were operated with ovary as Sham group for the control（Sham）.Other 30 rats were ovariectomized for OVX,OVX-E（Drenched 100μg/kg·d bw. d Diethylstilbestrol,DES）and OVX-D group（Drenched 100mg/kg·d bw Daidzein,Da）,10 in each one.After feeding 90 days, all of rats were killed to collect the blood and bone samples.The content of Ca,P,Mg,Zn,Mn in serum and bone were assayed. Results The results showed that the content of Ca,P,Mg,Zn in serum in OVX group were similar to those in Sham group,while P,Mg,Zn were decreased significantly in OVX-E and OVX-D groups compared to Sham groups（p＜0.01,p＜0.05）.The content of bone Ca and Zn in OVX-E and OVX-D groups were increased,compared with OVX group,accessing the normal lever.And then the ratio of Ca:P in serum and bone was increased by 36.4% or 48.6%(p＜0.01**).Conclusion:The Ca utilization and deposition in bone were increased because the higher ratio of Ca:P and lower level of P,Mg,Zn in serum were controlled by Da or DES.However,ALP in serum has relation with endogenous estrogen.

Key words: daidzein, Ca, Zn, ovariectomized female rats