Brunt L M, Veldhuis J D, Dilley W G, Farndon J R, Santen R J, Leight G S, Wells S A
J Clin Endocrinol Metab. 1986 Jan;62(1):210-6. doi: 10.1210/jcem-62-1-210.
The effects of calcium on fasting plasma insulin and glucose levels were compared in 16 normal subjects and 11 patients with beta-cell neoplasms of the pancreas. Calcium was administered iv either as a rapid calcium infusion (RCI; 2 mg/kg in 1 min) or as a long calcium infusion (LCI; 12 mg/kg in 3 h). In normal subjects, the RCI produced a rise in mean plasma insulin from 11 +/- 1 (+/- SEM) microU/ml basally to a peak of 18 +/- 2 microU/ml (P less than 0.001). No consistent pattern of change in insulin levels occurred during the LCI, and plasma glucose levels did not change significantly with either test. In the patients with beta-cell neoplasms, the RCI resulted in a rapid increase in mean plasma insulin from 36 +/- 6 microU/ml to a peak level of 312 +/- 67 microU/ml (P less than 0.002). With the LCI, a more gradual rise in insulin from 35 +/- 11 to 92 +/- 36 microU/ml occurred (P less than 0.002). The mean increase in insulin in the patients with beta-cell neoplasms was significantly greater for the RCI than for the LCI (P less than 0.01). Pronounced increments in plasma insulin occurred in all 11 patients after the RCI, but in only 3 of 8 patients during the LCI. Plasma glucose levels declined significantly from 69 +/- 7 to 56 +/- 8 mg/dl during the RCI (P less than 0.05) and from 69 +/- 8 to 49 +/- 7 mg/dl during the LCI (P less than 0.005). Symptomatic hypoglycemia developed in 3 patients during the LCI but did not occur after the RCI. These data indicate that calcium is a more effective insulin secretagogue in patients with beta-cell neoplasms when administered as an RCI than as an LCI, and suggest that the RCI may be a useful test for the diagnosis of insulin-secreting tumors.
在16名正常受试者和11名胰腺β细胞瘤患者中比较了钙对空腹血浆胰岛素和葡萄糖水平的影响。钙通过静脉注射给药，要么是快速钙输注（RCI；1分钟内注射2mg/kg），要么是长时间钙输注（LCI；3小时内注射12mg/kg）。在正常受试者中，RCI使平均血浆胰岛素从基础水平的11±1（±SEM）微单位/毫升升至峰值18±2微单位/毫升（P<0.001）。在LCI期间，胰岛素水平没有一致的变化模式，并且两种测试中血浆葡萄糖水平均未发生显著变化。在β细胞瘤患者中，RCI导致平均血浆胰岛素从36±6微单位/毫升迅速增加至峰值水平312±67微单位/毫升（P<0.002）。在LCI时，胰岛素从35±11微单位/毫升逐渐升至92±36微单位/毫升（P<0.002）。β细胞瘤患者中，RCI导致的胰岛素平均增加量显著大于LCI（P<0.01）。11名患者在RCI后血浆胰岛素均出现明显升高，但在LCI期间，8名患者中只有3名出现升高。在RCI期间，血浆葡萄糖水平从69±7毫克/分升降至56±8毫克/分升（P<0.05），在LCI期间从69±8毫克/分升降至49±7毫克/分升（P<0.005）。3名患者在LCI期间出现症状性低血糖，但在RCI后未发生。这些数据表明，对于β细胞瘤患者，以RCI方式给药时钙作为胰岛素促分泌剂比LCI更有效，并且提示RCI可能是诊断胰岛素分泌肿瘤的一种有用测试。
