EFFECTS OF PHYTOESTROGEN ON BONE LOSS IN OVARIECTOMIZED MICE.

染料木素是大豆中广泛存在的一种异黄酮类化合物，在结构上与雌激素相似，提示染料木素可能是一种植物雌激素。为探讨金雀异黄素在造血和骨代谢中的可能作用，将雌性小鼠分为假手术组和去卵巢组，用微量渗透压泵皮下注射染料木素2~4周(0.1~0.7 mg/d)或17β-雌二醇(0.0 1~0.1μg/d)。在OVX小鼠中，子宫重量下降，但经E2注射后完全恢复。相反，金雀异黄素并不能逆转OVX引起的子宫萎缩。去卵巢后2~4周，骨髓细胞数量明显增多，其中大部分为B220弱阳性的前B细胞。雌二醇组和金雀异黄素组均能完全恢复B淋巴细胞的增殖。在去卵巢小鼠中，通过MCT扫描和双能X射线吸收法测量的股骨远端干骺端的小梁体积显著减少，金雀异黄素恢复了这一体积，E2也是如此。这些结果表明，金雀异黄素在骨骼和骨髓中表现出雌激素样作用，调节B淋巴细胞的生成，防止骨丢失，而在子宫中不表现出雌激素作用。植物雌激素在子宫中可能是有用的雌激素作用。植物雌激素可能有助于防止女性因雌激素缺乏而导致的骨丢失。

Genistein, an isoflavone abundantly present in soybeans, has structural similarity to estrogen, suggesting that genistein may act as a phytoestrogen. To examine the possible role of genistein in hemopoiesis and bone metabolism, female mice were either sham-operated or ovariectomized (OVX), and selected OVX mice were administered genistein for 2-4 weeks (0.1-0.7 mg/day) or 17β-estradiol (E2) (0.01-0.1 μg/day) subcutaneously, using a mini-osmotic pump. In OVX mice, uterine weight declined, but was completely restored by E2 administration. In contrast, genistein did not demonstrate a reversal of the OVX-induced uterine atrophy. The number of bone marrow cells markedly increased 2-4 weeks after OVX, and most of these were B220-weakly positive pre-B cells. The increased B-lymphopoiesis was completely restored not only by E2, but also by genistein administration. In OVX mice, the trabecular one volume of the femoral distal metaphysis, measured by mCT scanning and dual energy X-ray absorptiometry, was markedly reduced, and genistein restored this, as did E2. These results indicate that genistein exhibits estrogenic action in bone and bone marrow to regulate B-lymphopoiesis and prevent bone loss, without exhibiting estrogenic action in the uterus. Phytoestrogens may be useful estrogenic action in the uterus. Phytoestrogens may be useful for preventing bone loss due to estrogen deficiency in females.