Shires R, Kessler G M
Division of Bone and Mineral Metabolism, Jewish Hospital, St. Louis, MO 63110.
Calcif Tissue Int. 1990 Sep;47(3):142-4. doi: 10.1007/BF02555978.
The use of calcium (Ca) supplements by postmenopausal women is growing rapidly. A commercial preparation of tricalcium phosphate (TCP) is available in the USA. Depending on the relative absorption of Ca versus phosphate, a rise in serum phosphorus (P) could stimulate parathyroid hormone (iPTH) secretion. We therefore compared Ca absorption and the metabolic responses following TCP to that of Ca carbonate (CC) on separate occasions in each of 10 women, aged 22-40 years. The subjects were fasted overnight for 12 hours while good hydration was maintained. Following a 2-hour baseline-urine collection, 1200 mg calcium (as CC or TCP) was ingested and two 2-hour postload urine collections were made. Blood was drawn at 1, 2, and 4 hours after the Ca load. Serum (S) and urine (U) Ca, P, and creatinine, and U cyclic AMP (cAMP) were determined. iPTH levels following TCP were also measured. Ca absorption was determined by the postload rise in Uca above baseline. Uca excretion increased significantly and was accompanied by significant rises in Sca after both preparations. Following TCP, S and U phosphorus increased. Urinary cAMP did not change after either preparation, and iPTH levels fell after oral TCP. We conclude that Ca taken as TCP is absorbed adequately and, thus, despite a rise in the S phosphorus level does not stimulate parathyroid activity.
绝经后女性使用钙（Ca）补充剂的情况正在迅速增加。美国有一种磷酸三钙（TCP）的商业制剂。根据钙与磷的相对吸收情况，血清磷（P）升高可能会刺激甲状旁腺激素（iPTH）分泌。因此，我们在10名年龄在22至40岁的女性中，分别比较了TCP和碳酸钙（CC）后的钙吸收及代谢反应。受试者禁食过夜12小时，同时保持良好的水合状态。在进行2小时的基线尿液收集后，摄入1200毫克钙（以CC或TCP形式），并进行两次2小时的负荷后尿液收集。在钙负荷后1、2和4小时采集血液。测定血清（S）和尿液（U）中的钙、磷、肌酐以及U环磷酸腺苷（cAMP）。还测量了TCP后的iPTH水平。钙吸收通过负荷后Uca高于基线的升高来确定。两种制剂后Uca排泄均显著增加，并伴有Sca的显著升高。服用TCP后，S和U磷升高。两种制剂后尿cAMP均未改变，口服TCP后iPTH水平下降。我们得出结论，以TCP形式摄入的钙吸收良好，因此，尽管S磷水平升高，但不会刺激甲状旁腺活动。
