Delvin E E, Salle B L, Glorieux F H, David L S
Shriners Hospital, Department of Surgery, Montreal, Canada.
Biol Neonate. 1988;53(6):321-6. doi: 10.1159/000242809.
Decrease in serum calcium level leading to hypocalcemia during the first week of life is a frequent finding in premature neonates. Eight premature neonates presenting with such an episode of hypocalcemia in the course of their first 4 days of life were studied. They were fed with a phosphate-enriched human milk and given vitamin D3 (2,100 IU/day per os). We have evaluated the effect of a 24-hour pharmacologic calcium infusion on the circulating levels of calcium, inorganic phosphate, magnesium, 25-hydroxycalciferol (25-OHD), 1 alpha,25-dihydroxycalciferol [1,25(OH)2D] and immunoreactive parathyroid hormone (iPTH). After the infusion, circulating iPTH and Pi levels dropped significantly (p less than 0.025 and p less than 0.005 respectively) whereas serum Ca and 25-OHD (p less than 0.005) increased. Mg and 1,25(OH)2D serum levels remained unchanged. Our data show that an increased calcium supply sustained for 24 h induces an appropriate response in iPTH secretion. Effects on circulating levels of 1,25(OH)2D were variable and probably reflected individual differences in half life of 1,25(OH)2D or in set points in the feedback mechanisms involved in the control of 1,25(OH)2D synthesis.
出生后第一周血清钙水平降低导致低钙血症是早产儿常见的表现。研究了8例在出生后前4天内出现低钙血症发作的早产儿。他们喂养富含磷的母乳并口服维生素D3（2100 IU/天）。我们评估了24小时药物性钙输注对钙、无机磷、镁、25-羟维生素D（25-OHD）、1α,25-二羟维生素D[1,25(OH)2D]和免疫反应性甲状旁腺激素（iPTH）循环水平的影响。输注后，循环iPTH和磷水平显著下降（分别为p<0.025和p<0.005），而血清钙和25-OHD升高（p<0.005）。镁和1,25(OH)2D血清水平保持不变。我们的数据表明，持续24小时增加钙供应会诱导iPTH分泌产生适当反应。对1,25(OH)2D循环水平的影响是可变的，可能反映了1,25(OH)2D半衰期或参与1,25(OH)2D合成控制的反馈机制设定点的个体差异。
