Body J J, Dumon J C, Seraj F, Cleeren A
Service de Médecine, Institut Jules Bordet, Université Libre de Bruxelles, Belgium.
J Clin Endocrinol Metab. 1992 Jun;74(6):1385-8. doi: 10.1210/jcem.74.6.1592885.
Spontaneous recovery of parathyroid secretion during correction of tumor-associated hypercalcemia by bisphosphonates provides a unique clinical opportunity to further unravel the complex relationship between Ca and PTH levels. We measured plasma ionised Ca (Ca2+) and serum intact PTH concentrations in 31 hypercalcemic cancer patients every 2 (range, 1-3) days over a period of 3-21 (median, 7) days after pamidronate therapy. The mean (+/- SD) initial Ca2+ concentration was 1.64 +/- 0.20 mmol/L (normal, 1.05-1.26 mmol/L), with a corresponding PTH level of 4.9 +/- 2.6 (median, 4.5; range, less than 2.0-14.7) ng/L. PTH levels were subnormal in 30 of 31 patients. During correction of hypercalcemia, the relationship between Ca2+ and PTH concentrations was best described by a polynomial regression (r = 0.89; P less than 0.001). The curve of the regression entered the normal range of PTH levels (10.5 ng/L) for a Ca2+ concentration of 1.21 mmol/L. Similarly, the mean Ca2+ level that caused a reproducible increase in PTH levels compared to baseline values was 1.21 +/- 0.12 (median, 1.17; range, 1.00-1.45) mmol/L. Comparable values were obtained when day to day variations in PTH levels were considered; the mean Ca2+ threshold level was 1.24 +/- 0.12 (median, 1.25; range, 1.00-1.43) mmol/L. This PTH secretory threshold was not significantly influenced by several factors, including the type of cancer hypercalcemia, the day to day variations in Ca2+ levels, various biochemical parameters of calcium metabolism, or the number of days to obtain a normal Ca2+ concentration. In summary, contrary to previous reports, our data show that the PTH secretory threshold during correction of tumor-associated hypercalcemia lies in the upper part of the normal range of Ca2+ concentrations and is not significantly influenced by the rate of change in Ca2+ levels.
在使用双膦酸盐纠正肿瘤相关性高钙血症过程中，甲状旁腺分泌的自发恢复为进一步阐明钙（Ca）与甲状旁腺激素（PTH）水平之间的复杂关系提供了一个独特的临床契机。我们对31例高钙血症癌症患者在帕米膦酸治疗后的3 - 21天（中位数为7天）内，每2天（范围1 - 3天）测量一次血浆离子钙（Ca2+）和血清完整PTH浓度。初始Ca2+浓度的均值（±标准差）为1.64±0.20 mmol/L（正常范围为1.05 - 1.26 mmol/L），相应的PTH水平为4.9±2.6（中位数为4.5；范围为低于2.0 - 14.7）ng/L。31例患者中有30例PTH水平低于正常。在纠正高钙血症过程中，Ca2+与PTH浓度之间的关系用多项式回归描述最佳（r = 0.89；P < 0.001）。回归曲线在Ca2+浓度为1.21 mmol/L时进入PTH水平的正常范围（10.5 ng/L）。同样，与基线值相比导致PTH水平可重复升高的平均Ca2+水平为1.21±0.12（中位数为1.17；范围为1.00 - 1.45）mmol/L。当考虑PTH水平的每日变化时获得了类似的值；平均Ca2+阈值水平为1.24±0.12（中位数为1.25；范围为1.00 - 1.43）mmol/L。这个PTH分泌阈值不受多种因素的显著影响，包括癌症高钙血症的类型、Ca2+水平的每日变化、钙代谢的各种生化参数或达到正常Ca2+浓度所需的天数。总之，与先前的报道相反，我们的数据表明在纠正肿瘤相关性高钙血症过程中PTH分泌阈值位于Ca2+浓度正常范围的上限，并且不受Ca2+水平变化速率的显著影响。
