Garner S C, Anderson J J, Mar M H, Parikh I
Department of Nutrition, School of Public Health, University of North Carolina, Chapel Hill 27599-7400.
Bone Miner. 1991 Oct;15(1):19-31. doi: 10.1016/0169-6009(91)90108-c.
Estrogen treatment of ovariectomized, lactating rats improved retention of bone mineral mass by 15-25% compared to ovariectomized, lactating rats receiving vehicle only. On the second day postpartum all lactating rats were ovariectomized and were placed along with age-matched non-mated controls on a whole-wheat flour-based diet with 0.1% calcium and 0.4% phosphorus. On day 6 postpartum estrogen treatment was begun with either implantation of a slow-release 17 beta-estradiol pellet or with the first of daily subcutaneous injections in sesame oil (vehicle). Increasing doses of estrogen resulted in decreased food consumption and decreased litter weight gain, both well-known effects of estrogens. Ovariectomized, lactating rats implanted with a slow-release pellet containing 0.35 mg 17 beta-estradiol had mean serum estradiol levels of 113.5 pg/ml. At the end of 21 days of lactation, femurs of dams with placebo pellets showed loss of 54% of bone ash weight compared with the non-mated controls versus only 42% loss by rats receiving estradiol treatment. Rats were also injected with estradiol benzoate in a sesame oil vehicle at 3 dose levels of 1.6, 5, or 16 micrograms/day. Only the 5 and 16 micrograms/day doses significantly improved retention of bone mineral mass during lactation (+17% and +18%, respectively, vs vehicle-injected, lactating rats). Estrone administered by subcutaneous injection also improved retention of bone during lactation; however, injection of 50 micrograms/day of estrone was required to produce an equivalent bone retention compared to 5 micrograms/day of estradiol. Thus, treatment of ovariectomized, lactating rats with estrogens results in a significant reduction of the loss of bone mineral mass associated with lactation.
与仅接受赋形剂的去卵巢泌乳大鼠相比，对去卵巢泌乳大鼠进行雌激素治疗可使骨矿物质含量保留率提高15%-25%。产后第二天，所有泌乳大鼠均接受去卵巢手术，并与年龄匹配的未交配对照大鼠一起，置于以全麦面粉为基础、钙含量为0.1%、磷含量为0.4%的饮食中。产后第6天开始雌激素治疗，方法为植入缓释17β-雌二醇药丸或开始每日皮下注射芝麻油（赋形剂）。雌激素剂量增加导致食物摄入量减少和窝仔体重增加减少，这两种都是雌激素的众所周知的作用。植入含0.35mg 17β-雌二醇缓释药丸的去卵巢泌乳大鼠的平均血清雌二醇水平为113.5pg/ml。泌乳21天结束时，与未交配对照大鼠相比，接受安慰剂药丸的母鼠股骨骨灰重量损失54%，而接受雌二醇治疗的大鼠仅损失42%。大鼠还以1.6、5或16微克/天的3种剂量水平接受苯甲酸雌二醇的芝麻油赋形剂注射。只有5微克/天和16微克/天的剂量在泌乳期间显著提高了骨矿物质含量的保留率（分别比注射赋形剂的泌乳大鼠提高17%和18%）。皮下注射雌酮也可改善泌乳期间的骨保留；然而，与5微克/天的雌二醇相比，需要注射50微克/天的雌酮才能产生同等的骨保留效果。因此，用雌激素治疗去卵巢泌乳大鼠可显著减少与泌乳相关的骨矿物质含量损失。
