Anterior and posterior pituitary function testing with simultaneous insulin tolerance test and a novel copeptin assay
Anterior and posterior pituitary function testing with simultaneous insulin tolerance test and a novel copeptin assay
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DOI：
10.1210/jc.2006-2046
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发表时间：
2007-07-01
影响因子：
5.8
通讯作者：
Christ-Crain, Mirjam
中科院分区：
文献类型：
--
作者：
Katan, Mira;Morgenthaler, Nils G.;Christ-Crain, Mirjam
背景：怀疑尿崩症患者的垂体后叶功能通常通过缺水试验来评估。另外，非渗透性刺激如低血糖可用于刺激抗利尿激素[精氨酸抗利尿激素（AVP）]的分泌。血浆AVP测定可能有助于诊断，特别是尿崩症和多饮的鉴别诊断。然而，AVP测量是繁琐的。Copeptin是AVP原激素的稳定的c端糖肽，从垂体后叶分泌。目的：探讨copeptin水平在胰岛素性低血糖尿崩症诊断中的价值。患者和方法：共有38例患者在胰岛素诱导的低血糖期间被研究，作为可能的垂体前叶疾病的联合垂体功能检查的一部分。垂体后叶功能正常者29例，中枢性尿崩症9例。分别于静脉注射胰岛素前、30min、45min、90min采血。Copeptin用一种新的夹心免疫分析法测定。结果：垂体后叶功能完好的患者基础copeptin水平为3.7 +/- 1.5 pM，注射胰岛素45 min后最大升高至11.1 +/- 4.6 pM。尿崩症患者注射胰岛素前Copeptin水平为2.4 +/- 0.5 pM，最高可增至3.7 +/- 0.7 pM。与垂体后叶功能完整的患者相比，尿崩症患者的基础和刺激copeptin水平均较低。注射胰岛素后小于4.75 pM 45 min刺激copeptin水平对尿囊症的诊断准确率最佳。结论：Copeptin测定可用于评估胰岛素性低血糖时垂体后叶和前叶的功能。
Context: Posterior pituitary function in patients with suspected diabetes insipidus is usually assessed by a water deprivation test. Alternatively, a nonosmotic stimulus such as hypoglycemia may be used to stimulate vasopressin [ arginine vasopressin ( AVP)] secretion. Plasma AVP measurement may aid in the diagnosis and, especially, differential diagnosis of diabetes insipidus and polydipsia. However, AVP measurement is cumbersome. Copeptin, the stable C-terminal glycopeptide of the AVP prohormone, is stoichiometrically secreted from the posterior pituitary.Objective: The aim was to study the value of copeptin levels in the diagnosis of diabetes insipidus during insulin-induced hypoglycemia.Patients and Methods: A total of 38 patients were studied during insulin-induced hypoglycemia as part of a combined pituitary function test for possible anterior pituitary disease. There were 29 patients who had normal posterior pituitary function, and nine had central diabetes insipidus. Blood sampling was done before and 30, 45, and 90 min after iv insulin injection. Copeptin was measured with a new sandwich immunoassay.Results: Patients with intact posterior pituitary function had basal copeptin levels of 3.7 +/- 1.5 pM, with a maximal increase to 11.1 +/- 4.6 pM 45 min after insulin injection. Copeptin levels in patients with diabetes insipidus were 2.4 +/- 0.5 pM before insulin injection, with a maximum increase to 3.7 +/- 0.7 pM. Both basal and stimulated copeptin levels were lower in patients with diabetes insipidus as compared with patients with intact posterior pituitary function. A stimulated copeptin level 45 min after insulin injection of less than 4.75 pM had an optimal diagnostic accuracy to detect diabetes insipidus. Conclusion: Copeptin measurement may be used to assess posterior together with anterior pituitary function during insulin-induced hypoglycemia.