Stewart A F, Horst R, Deftos L J, Cadman E C, Lang R, Broadus A E
N Engl J Med. 1980 Dec 11;303(24):1377-83. doi: 10.1056/NEJM198012113032401.
In 50 consecutive patients with cancer-associated hypercalcemia, we measured nephrogenous cyclic AMP, tubular phosphorus threshold, fasting calcium excretion, plasma 1,25-dihydroxyvitamin D, and immunoreactive parathyroid hormone as determined by four region-specific antiserums. Nephrogenous cyclic AMP excretion was elevated in 41 patients and suppressed in nine (means, 5.85 vs. 0.51 nmol per 100 ml of glomerular filtrate). There was no overlap between these groups. When compared with 15 patients with primary hyperparathyroidism, the group with increased cyclic AMP excretion had similar reductions in tubular phosphorus threshold; higher fasting calcium excretion (means, 0.66 vs. 0.25 mg per 100 ml of glomerular filtrate, P < 0.01); marked reductions in 1,25-dihydroxyvitamin D (means, 20 vs. 83 pg per milliliter, P < 0.001); and lower levels of immunoreactive parathyroid hormone in all four assays. The data suggest that elevated excretion of nephrogenous cyclic AMP may be a useful marker of humorally mediated cancer-associated hypercalcemia, that this type of hypercalcemia is common, that the humoral factor responsible for this syndrome is not native 1-84 parathyroid hormone, and that the various subtypes of cancer-associated hypercalcemia are biochemically distinguishable from primary hyperparathyroidism.
在连续50例癌症相关性高钙血症患者中，我们测定了肾源性环磷酸腺苷（cAMP）、肾小管磷阈值、空腹钙排泄量、血浆1,25 - 二羟维生素D以及通过四种区域特异性抗血清测定的免疫反应性甲状旁腺激素。41例患者肾源性cAMP排泄升高，9例受抑制（平均值分别为每100ml肾小球滤过液5.85和0.51nmol）。这两组之间没有重叠。与15例原发性甲状旁腺功能亢进患者相比，cAMP排泄增加组的肾小管磷阈值有类似降低；空腹钙排泄更高（平均值分别为每100ml肾小球滤过液0.66和0.25mg，P<0.01）；1,25 - 二羟维生素D显著降低（平均值分别为每毫升20和83pg，P<0.001）；并且在所有四种检测中免疫反应性甲状旁腺激素水平更低。数据表明，肾源性cAMP排泄升高可能是体液介导的癌症相关性高钙血症的一个有用标志物，这种类型的高钙血症很常见，导致该综合征的体液因子不是天然的1 - 84甲状旁腺激素，并且癌症相关性高钙血症的各种亚型在生化方面可与原发性甲状旁腺功能亢进相区分。
