Sips A J, van der Vijgh W J, Barto R, Netelenbos J C
Department of Endocrinology, Free University Hospital, Amsterdam, The Netherlands.
Clin Chem. 1995 Oct;41(10):1446-50.
Calcium absorption tests have rarely been validated for being representative for absolute bioavailability (true absorption) or for intraindividual variation. Therefore, we investigated the reproducibility of the absolute bioavailability of strontium chloride, a marker for intestinal calcium absorption, in healthy male volunteers (n = 8) by measuring the area under the plasma strontium concentration-time curve after oral and intravenous administration of strontium. Subsequently, we selected a simple test variable as being representative of absolute bioavailability. The mean absolute bioavailability (+/- SD) was 25% +/- 7%. The best test variable appeared to be the fractional absorption at 240 min (Fc240) after oral intake, which demonstrated the highest correlation with absolute bioavailability (r = 0.66). The intraindividual variations of the data for this variable and for the absolute bioavailability are similar to those described for various absorption tests based on the use of calcium isotopes. Thus, the Fc240 of strontium offers the potential of a simple clinical test for use as a measure of intestinal calcium absorption and its modulation.
钙吸收试验很少经过验证，以确定其是否能代表绝对生物利用度（真正的吸收）或个体内差异。因此，我们通过测量口服和静脉注射锶后血浆锶浓度-时间曲线下的面积，研究了健康男性志愿者（n = 8）中作为肠道钙吸收标志物的氯化锶绝对生物利用度的可重复性。随后，我们选择了一个简单的测试变量来代表绝对生物利用度。平均绝对生物利用度（±标准差）为25%±7%。最佳测试变量似乎是口服后240分钟的吸收分数（Fc240），它与绝对生物利用度的相关性最高（r = 0.66）。该变量数据和绝对生物利用度的个体内变异与基于钙同位素使用的各种吸收试验所描述的相似。因此，锶的Fc240提供了一种简单的临床试验潜力，可作为肠道钙吸收及其调节的一种测量方法。
