Shimamoto K, Higashiura K, Nakagawa M, Masuda A, Shiiki M, Miyazaki Y, Ise T, Fukuoka M, Hirata A, Iimura O
Second Department of Internal Medicine, Sapporo Medical, University School of Medicine, Japan.
Tohoku J Exp Med. 1995 Dec;177(4):271-8. doi: 10.1620/tjem.177.271.
The effect of acute insulin infusion on the metabolism of calcium (Ca) and phosphate (P) was examined in 17 healthy subjects. They were hospitalized and kept on a constant diet for 5 days, and an euglycemic hyperinsulinemic glucose clamp was applied. Synthetic human insulin was infused at the rate of 40 mU/m2/min for 2 hr, and glucose was also infused to maintain basal glucose levels of each subject. The control study was performed in 8 of the 17 subjects, into whom 10% xylitol was infused for 2 hr at the rate of 100 ml/hr. The plasma insulin concentrations were 7.94 +/- 0.35 and 62.3 +/- 14.3 mU/liter before and after the glucose clamp technique, but serum free Ca ion was increased significantly (p < 0.05), and serum P and serum parathyroid hormone (PTH) were decreased significantly (p < 0.001). Creatinine clearance did not change during the glucose clamp technique. Urinary excretion of Ca (UCaV) was significantly higher after the glucose clamp than the control study. Fractional excretion of Ca (FECa) was increased significantly (p < 0.05), and urinary excretion of P (UPV) and fractional excretion of P (FEP) were decreased significantly (p < 0.05) under the hyperinsulinemic condition. The results suggested that, under the conditions of euglycemic hyperinsulinemia by glucose clamp technique, insulin increased the serum free Ca ion, and as a result, PTH was suppressed. Decreased PTH might induce calciuresis and enhance tubular P reabsorption under hyperinsulinemia. Insulin increased serum free Ca ion might relate to the vasodilating action of insulin by its decrease of intracellular free Ca ion in vascular smooth muscle.
在17名健康受试者中研究了急性输注胰岛素对钙（Ca）和磷（P）代谢的影响。他们住院并持续5天保持恒定饮食，然后进行了正常血糖高胰岛素葡萄糖钳夹试验。以40 mU/m²/分钟的速率输注合成人胰岛素2小时，同时也输注葡萄糖以维持每个受试者的基础血糖水平。在17名受试者中的8名中进行了对照研究，以100 ml/小时的速率向他们输注10%木糖醇2小时。葡萄糖钳夹技术前后血浆胰岛素浓度分别为7.94±0.35和62.3±14.3 mU/升，但血清游离钙离子显著升高（p<0.05），血清磷和血清甲状旁腺激素（PTH）显著降低（p<0.001）。在葡萄糖钳夹技术期间肌酐清除率没有变化。葡萄糖钳夹试验后尿钙排泄量（UCaV）显著高于对照研究。在高胰岛素血症条件下，钙分数排泄（FECa）显著增加（p<0.05），尿磷排泄量（UPV）和磷分数排泄（FEP）显著降低（p<0.05）。结果表明，在通过葡萄糖钳夹技术实现正常血糖高胰岛素血症的条件下，胰岛素增加了血清游离钙离子，结果导致PTH受到抑制。PTH降低可能在高胰岛素血症时诱导钙尿并增强肾小管对磷的重吸收。胰岛素增加血清游离钙离子可能与其通过降低血管平滑肌细胞内游离钙离子的血管舒张作用有关。
