Goulding A, Gold E
Medicine Department, University of Otago Medical School, Dunedin, New Zealand.
Calcif Tissue Int. 1990 Jan;46(1):14-9. doi: 10.1007/BF02555819.
In the rat, prolonged administration of the luteinizing, hormone-releasing hormone agonist buserelin (25 micrograms/kg body wt/day s.c.) lowers blood estradiol, raises bone resorption, and induces osteopenia. The present study was undertaken to determine whether withdrawal of buserelin normalizes blood estradiol, slows bone resorption, and corrects buserelin-mediated osteopenia. Four groups of female rats with 45Ca-labeled bones were studied: group 1A received 0.2 ml saline s.c. daily for 4 weeks; group 2A received 0.2 ml buserelin s.c. daily for 4 weeks; group 1B received 0.2 ml saline s.c. daily for 8 weeks; group 2B received 0.2 ml buserelin s.c. daily for 4 weeks followed by 0.2 ml saline s.c. daily for 4 weeks. Bone resorption was monitored by measuring urinary 45Ca and hydroxyproline. The rats in groups 1A and 2A were killed after 4 weeks and those in groups 1B and 2B after 8 weeks. The mineral contents of the femoral bones and the whole skeletons were measured. Buserelin lowered blood estradiol, elevated urinary 45Ca and urinary hydroxyproline, and lowered femur and total body calcium and 45Ca in group 2A vs. 1A (P less than 0.05). By contrast all these measurements became similar in groups 2B and 1B. Thus, osteopenia generated by a 4-week period of buserelin-mediated hypo-estrogenism is reversible by withdrawing buserelin for 4 weeks. Consequently, buserelin administration and withdrawal may be used to study effects of inducing and reversing estrogen-deficiency bone loss in the rat.
在大鼠中，长期给予促黄体生成素释放激素激动剂布舍瑞林（25微克/千克体重/天，皮下注射）可降低血液雌二醇水平，增加骨吸收，并诱发骨质减少。本研究旨在确定停用布舍瑞林是否能使血液雌二醇水平恢复正常，减缓骨吸收，并纠正布舍瑞林介导的骨质减少。对四组骨骼用45Ca标记的雌性大鼠进行了研究：1A组每天皮下注射0.2毫升生理盐水，持续4周；2A组每天皮下注射0.2毫升布舍瑞林，持续4周；1B组每天皮下注射0.2毫升生理盐水，持续8周；2B组每天皮下注射0.2毫升布舍瑞林，持续4周，随后每天皮下注射0.2毫升生理盐水，持续4周。通过测量尿45Ca和羟脯氨酸来监测骨吸收。1A组和2A组的大鼠在4周后处死，1B组和2B组的大鼠在8周后处死。测量股骨和整个骨骼的矿物质含量。与1A组相比，2A组中布舍瑞林降低了血液雌二醇水平，升高了尿45Ca和尿羟脯氨酸水平，并降低了股骨和全身的钙及45Ca含量（P<0.05）。相比之下，2B组和1B组的所有这些测量结果变得相似。因此，布舍瑞林介导的低雌激素状态持续4周所产生的骨质减少，通过停用布舍瑞林4周是可逆的。因此，给予和停用布舍瑞林可用于研究大鼠诱导和逆转雌激素缺乏性骨质流失的作用。
