Valenzuela G J, Munson L A, Tarbaux N M, Farley J R
Dept. of Obstetrics & Gynecology, San Bernadino County Medical Center, CA.
Clin Chem. 1987 Oct;33(10):1801-6.
To measure changes in bone alkaline phosphatase (EC 3.1.3.1) activity in serum as a function of duration of pregnancy, we adapted our existing alkaline phosphatase (ALP) isoenzyme assay (which has been used to measure bone, hepatic, and intestinal ALP activities in serum, in the absence of placental ALP) to allow quantification of individual ALP isoenzyme activities in the presence of placental ALP. The resulting CV for repeat measurements of bone ALP activity in artificial isoenzyme mixtures ranged from 23% for samples in which the bone isoenzyme represented 7% of total ALP activity to 11% for samples in which bone ALP accounted for 48% of total ALP activity. Values for repeat determinations of bone ALP activity in human serum samples (i.e., including samples obtained from pregnant women and from nonpregnant controls) varied by an average of 18%. We find, in initial applications of this method, that (a) the amount of bone ALP activity in serum is increased during pregnancy (P less than .001), and remains increased at six weeks postpartum, in non-lactating women (P less than .001), and (b) bone ALP activity at term was not significantly different in pregnant women with pre-eclampsia, diabetes, premature rupture of membranes, or premature labor, compared with normal pregnancies at term. Our data support the hypothesis that maternal bone formation may be increased during pregnancy.
为了测量血清中骨碱性磷酸酶（EC 3.1.3.1）活性随孕期的变化，我们对现有的碱性磷酸酶（ALP）同工酶检测方法（该方法在不存在胎盘ALP的情况下，已用于测量血清中的骨、肝和肠ALP活性）进行了调整，以便在存在胎盘ALP的情况下对各个ALP同工酶活性进行定量。在人工同工酶混合物中对骨ALP活性进行重复测量时，所得的变异系数（CV）范围为：骨同工酶占总ALP活性7%的样本为23%，骨ALP占总ALP活性48%的样本为11%。在人类血清样本（即包括从孕妇和非孕妇对照中获得的样本）中对骨ALP活性进行重复测定的值平均变化18%。我们在该方法的初步应用中发现：（a）孕期血清中骨ALP活性增加（P<0.001），在产后六周，非哺乳期妇女中仍保持增加（P<0.001）；（b）与足月正常妊娠相比，患有先兆子痫、糖尿病、胎膜早破或早产的孕妇足月时的骨ALP活性无显著差异。我们的数据支持孕期母体骨形成可能增加这一假说。
