中文摘要：

钙是人体所必需的元素之一,参与众多的生命生理调控,准确测量生物体的钙吸收率,对于合理补钙和预防钙代谢疾病具有重要意义。本研究采用41 Ca标记SD大鼠体内钙库,利用加速器质谱（AMS）法测量长寿命放射性核素41 Ca灵敏度高的特点,开展对大鼠钙吸收率的准确测定。结果表明：大鼠每100g体重每天摄入28 mg碳酸钙、28 mg柠檬酸钙、10 mg碳酸钙的表观吸收率分别为（67.57±2.79）%、（65.21±2.96）%、（87.50±1.10）%,净吸收率分别为（73.19±3.60）%、（71.47±4.01）%、（92.74±1.81）%。该方法可以得出钙的真实吸收率,且不受所评价的钙剂中钙的化学形式和种类的影响,进一步拓展了同位素评价钙吸收率的应用领域,可为建立适宜于我国人民的钙参考摄入量标准提供实验依据。

英文摘要：

Calcium is one of the essential elements that form human bone（the main form of calcium is Ca10（PO4）6（OH）2））,and it participates and regulates many life processes.Osteoporosis is the most common disease of calcium deficiency,while recent research shows that organisms（especially osteoporosis organisms）take in too much calcium,possibly causing some other diseases.Thus,the accuracy of calcium absorption rate measurement is very meaningful for reasonable calcium supplement and prevention diseases of calcium metabolism.Based on the high sensitivity of 41 Ca measurement with accelerator mass spectrometry and the innovative methods of 41 Ca labeling endogenous calcium,thecalcium absorption rate of rats was studied.The results show that rats intake 28 mg calcium carbonate,28 mg calcium citrate and 10 mg calcium citrate per 100 g body weight each day,the apparent absorption rates are（67.57±2.79）%,（65.21±2.96）%and（87.50±1.10）%,the static absorption rates are（73.19±3.60）%,（71.47±4.01）%and（92.74±1.81）%,respectively.This method can obtain the true absorption of calcium without extrinsic labeling,and it is not affected by the chemical structure and sorts of calcium supplements.