Stimulatory effect of daidzein in osteoblastic MC3T3-E1 cells

Daldzein is a natural isoflavone found in Leguminosae. The effect of daidze in on osteoblastic MC3T3-E1 cells was investigated. Cells were cultured in a serum-free medium for 48 hr in the presence of daidzein (10(-7)-10(-5) M) . Daidzein (10(-6) and 10(-5) M) caused:a significant elevation of protein content, alkaline phosphatase activity, and DNA content in cells; those inc reases were about 1.4-, 1.5-, and 2.0-fold, respectively. The ability of da idzein (10(-5) M) to increase protein content, alkaline phosphatase activit y, and DNA content in cells was prevented completely by the presence of cyc loheximide (10(-6) M), an inhibitor of protein synthesis, indicating that t he isoflavone has a stimulatory effect: on cellular protein synthesis. The anabolic effect of -daidzein (10(-6) or 10(-5) M) in cells was not distingu ishable from that of genistein (10(-6) or 10(-5) M). Meanwhile, cell protei n showed an additive effect of 17 beta-estradiol and daidzein, hut their ef fects on alkaline phosphatase were not additive. Moreover, the effect of da idzein (10(-5) M) in elevating cellular protein content and alkaline phosph atase activity was inhibited completely by the presence of tamoxifen (10(-6 ) M), suggesting chat the effect of the isoflavone is mediated partly throu gh estrogen action. This study demonstrates that daidzein has an anabolic e ffect in osteoblastic MC3T3-E1 cells. (C) 2000 Elsevier Science Inc.