RESUMEN
Aim To compare the pharmacological ac-tivity of icariin( ICA) and genistien ( GEN) against os-teoporosis after oral administration with them to growing rats and ovariectomized rats. Methods 25 mg·kg-1 icariin and 10 mg · kg-1 genistein ( equal in molar concentration) were administered to one-month-old fe-male SD rats every day for three months. Treatments at the same dosage were administered to the 6-month-old ovariectomized SD rats every day for three months. Their effects were compared on bone mineral density and biomechanical properties of femurs and vertebrae, serum levels of osteocalcin and tartaric acid phospha-tase 5b ( TRACP 5b) and histomorphometry. Results The results showed that, in young rats, icariin treat-ment significantly increased bone mineral density, the maximum mechanical loads of femurs and vertebrae as well as the bone qualities ( serum markers and microar-chitecture ) , whereas genistein treatment had little effects compared with the non-treatment control. How-ever, genistein treatment was more efficacious than icariin in preventing bone loss and deterioration of bone microarchitecture in ovariectomized rats. Conclusion Our data suggest that, since icariin has a higher os-teogenic activity but lower estrogenic activity, it has been found to be more efficacious than genistein in peak bone mass accrual only in young rats. In the ovariectimized rats, however, as the main force to pre-vent bone loss is the estrogenic activity, genistein has been found to be more efficacious than icariin in reduc-ing bone loss.