Cholst I N, Steinberg S F, Tropper P J, Fox H E, Segre G V, Bilezikian J P
N Engl J Med. 1984 May 10;310(19):1221-5. doi: 10.1056/NEJM198405103101904.
We measured serum concentrations of calcium and parathyroid hormone in seven pregnant women who were receiving intravenous magnesium sulfate for the suppression of premature labor. After administration of magnesium sulfate, the mean (+/- S.E.M.) serum magnesium level rose rapidly from the normal base-line level of 2.0 +/- 0.2 mg per deciliter to 6.1 +/- 0.4 mg per deciliter (0.8 +/- 0.1 to 2.5 +/- 0.2 mmol per liter) (P less than 0.001) at 30 minutes and remained markedly elevated. Concentrations of total and ionized calcium fell gradually in all subjects from normal base-line concentrations, 8.6 +/- 0.2 and 4.4 +/- 0.1 mg per deciliter (2.2 +/- 0.1 and 1.1 +/- 0.03 mmol per liter), respectively, into the hypocalcemic range, reaching a nadir of 7.6 +/- 0.2 and 3.9 +/- 0.1 mg per deciliter (1.9 +/- 0.1 and 0.98 +/- 0.03 mmol per liter), respectively, at three hours (P less than 0.001). Parathyroid hormone levels fell rapidly in response to magnesium infusion, from 13.1 +/- 2.5 to 7.8 +/- 0.7 pg per milliliter at 30 minutes, and were significantly below base-line levels for two hours despite frank hypocalcemia. These results suggest that hypermagnesemia rapidly decreases the secretion of parathyroid hormone in vivo in human subjects and that parathyroid hormone levels remain depressed despite concomitant hypocalcemia. The results also suggest that the hypocalcemia associated with hypermagnesemia may be due in part to the suppressive effects of hypermagnesemia on parathyroid hormone secretion.
我们测量了7名接受静脉注射硫酸镁以抑制早产的孕妇的血清钙和甲状旁腺激素浓度。注射硫酸镁后，平均（±标准误）血清镁水平在30分钟时迅速从正常基线水平2.0±0.2毫克/分升升至6.1±0.4毫克/分升（0.8±0.1至2.5±0.2毫摩尔/升）（P<0.001），并持续显著升高。所有受试者的总钙和离子钙浓度均从正常基线浓度（分别为8.6±0.2和4.4±0.1毫克/分升，即2.2±0.1和1.1±0.03毫摩尔/升）逐渐下降至低钙血症范围，在3小时时分别降至最低点7.6±0.2和3.9±0.1毫克/分升（1.9±0.1和0.98±0.03毫摩尔/升）（P<0.001）。甲状旁腺激素水平在输注镁后迅速下降，30分钟时从13.1±2.5降至7.8±0.7皮克/毫升，尽管存在明显的低钙血症，但在两小时内显著低于基线水平。这些结果表明，高镁血症可迅速降低人体受试者体内甲状旁腺激素的分泌，且尽管同时存在低钙血症，甲状旁腺激素水平仍保持降低。结果还表明，与高镁血症相关的低钙血症可能部分归因于高镁血症对甲状旁腺激素分泌的抑制作用。
