中文摘要：

为研究来曲唑对蛋鸡髓质骨形成的影响,阐明髓质骨形成的机制,选用210羽14周龄伊莎母鸡,预饲1周后随机杀10羽取骨骼样本作为背景对照;剩余母鸡随机平均分为2组,试验组经口给予来曲唑0.5 mg.d^-1.只^-1,另一组作为对照组,试验为期18 d。结果显示,与对照组相比,来曲唑可极显著降低鸡体内雌激素水平和雌激素受体的表达（P〈0.01）,显著提高雄激素水平（P〈0.05）;显著提高胫骨骨皮质指数,降低骨放射密度（P〈0.05）;胫骨外骨膜周长、内骨膜周长、皮质骨面积、平均皮质骨厚度、皮质骨面积比例差异不显著（P〉0.05）。本研究表明来曲唑能抑制雌激素合成,阻止髓质骨的形成,减缓骨骼生长。

英文摘要：

In order to study the effect of letrozole on medullary bone osteogenesis and elucidate the mechanism of medullary bone osteogenesis in layer,210 ISA pullets of 14-week old were fed for one week before experiment,then 10 birds selected randomly from the total group were killed for collecting bone samples;the rest were averagely divided into two groups at random,control and the treated group.Animals of the treated group were fed with letrozole at 0.5 mg·d^-1·hen^-1,and the experiment lasted for 18 days.The results showed that letrozole could decrease the level of estrogen and the expression of estrogen receptor extremely significant（P〈0.01）,increase the level of androgen significantly（P〈0.05）,increase the bone cortex index significantly（P〈0.05）and decrease the bone radiographic density of tibia significantly（P〈0.05）.However,the periosteum and endosteum perimeter,cortical width and cortical area ratio of both the two groups were not significant（P〉0.05）.It revealed that letrozole can inhibit the synthesization of estrogen,decrease the growth of bone and prevent the osteogenesis of medullary bone.