Schwarz P, Sørensen H A, Transbøl I, McNair P
Department of Clinical Chemistry, Hvidovre Hospital, Denmark.
Scand J Clin Lab Invest. 1990 Dec;50(8):891-7. doi: 10.3109/00365519009104958.
In order to investigate (1) the possibility of controlled induction and maintenance of hypocalcaemia, and (2) the intact parathyroid hormone (PTH(1-84)) response obtained thereby, 14 healthy individuals were administered an i.v. infusion of trisodiumcitrate. The reproducibility of the method established was assessed in five of the 14 individuals. Aiming at a steady-state level of blood ionized calcium (B-Ca2+) = 1.00 mmol/l, obtained within 30 min and subsequently maintained for 90 min, the infusion was guided by frequent determinations B-Ca2+. The method established was as follows: infusion of 0.85 mmol citrate/kg body weight/h during the first 10 min, followed by 0.44 mmol citrate/kg body wt h 1.26 exp. ((actual B-Ca2(+)--target B-Ca2+)/0.02) mmol/l, until B-Ca2+ = 1.00 mmol/l. In the steady-state period the infusion rate was 0.29 mmol citrate/kg body wt. h 1.26 exp. ((actual B-Ca2(+)--target B-Ca2+)/0.02) mmol/l. The method showed reproducibility by an overall difference in B-Ca2+ measurements of -0.03 mmol/l, which did not statistically differ from zero (p less than 0.05). No severe side effects were observed during a total of 21 infusions. Intact serum parathyroid hormone concentrations (S-PTH(1-84)) obtained during induced hypocalcaemia rose to a peak within 5-10 min, and then declined to a steady-state level about three times the initial. The serum (S) PTH(1-84) response could be caused by a burst of S-PTH(1-84) from a depot source while the steady-state level may indicate a stimulated secretion from parathyroid glands. The S-PTH(1-84) response was shown to be reproducible by an overall difference in S-PTH(1-84) measurements of -0.52 pmol/l, which did not statistically differ from zero (p less than 0.10).
（1）可控诱导和维持低钙血症的可能性，以及（2）由此获得的完整甲状旁腺激素（PTH(1 - 84)）反应，对14名健康个体静脉输注柠檬酸钠。在这14名个体中的5名中评估了所建立方法的可重复性。目标是在30分钟内达到并随后维持90分钟的稳态血离子钙（B - Ca2 +）水平为1.00 mmol/l，输注过程通过频繁测定B - Ca2 +来指导。所建立的方法如下：在最初10分钟内以0.85 mmol柠檬酸盐/千克体重/小时的速度输注，随后以0.44 mmol柠檬酸盐/千克体重·小时×1.26^((实际B - Ca2(+) - 目标B - Ca2+)/0.02) mmol/l的速度输注，直至B - Ca2 + = 1.00 mmol/l。在稳态期，输注速度为0.29 mmol柠檬酸盐/千克体重·小时×1.26^((实际B - Ca2(+) - 目标B - Ca2+)/0.02) mmol/l。该方法显示出可重复性，B - Ca2 +测量的总体差异为 - 0.03 mmol/l，与零无统计学差异（p < 0.05）。在总共21次输注过程中未观察到严重副作用。诱导低钙血症期间获得的完整血清甲状旁腺激素浓度（S - PTH(1 - 84)）在5 - 10分钟内升至峰值，然后降至约初始值三倍的稳态水平。血清（S）PTH(1 - 84)反应可能是由储存库来源的S - PTH(1 - 84)突然释放引起的，而稳态水平可能表明甲状旁腺受到刺激后的分泌。S - PTH(1 - 84)反应显示出可重复性，S - PTH(1 - 84)测量的总体差异为 - 0.52 pmol/l，与零无统计学差异（p < 0.10）。
