Szinnai Gabor, Morgenthaler Nils G, Berneis Kaspar, Struck Joachim, Müller Beat, Keller Ulrich, Christ-Crain Mirjam
Division of Endocrinology, Diabetology, and Clinical Nutrition, University Hospital, CH-4031 Basel, Switzerland.
J Clin Endocrinol Metab. 2007 Oct;92(10):3973-8. doi: 10.1210/jc.2007-0232. Epub 2007 Jul 17.
The measurement of arginine vasopressin (AVP) is often cumbersome because it is unstable with a short half-life time. AVP is derived from a larger precursor peptide along with the more stable peptide copeptin. Copeptin is the C-terminal part of provasopressin and has been shown to be a useful tool to indicate AVP concentration in critically ill patients.
The objective of the study was to evaluate the clinical usefulness of copeptin as a new marker in disordered states of blood volume and plasma osmolality.
This was a prospective observational study in a university hospital.
Three techniques with respective control studies were used in 24 healthy adults to produce changes in plasma osmolality and/or volume: 1) a 28-h water deprivation, 2) a 17-h hypertonic saline infusion combined with thirsting, and 3) a hypotonic saline infusion with iv desmopressin administration during free water intake.
Water deprivation produced a weight loss of 1.7 kg, an increase in plasma osmolality to 294.8 +/- 4.3 mosmol/kg, and an increase of copeptin from 4.6 +/- 1.7 pmol/liter to 9.2 +/- 5.2 pmol/liter (P < 0.0001). During hypertonic saline infusion and thirsting with a raise of plasma osmolality to 296.1 +/- 3.4 mosmol/kg, copeptin increased from 4.9 +/- 3.0 pmol/liter to 19.9 +/- 4.8 pmol/liter (P < 0.0001). Conversely, during hypotonic saline infusion, plasma osmolality decreased to 271.3 +/- 4.1 mosmol/kg, and copeptin decreased from 6.2 +/- 2.4 pmol/liter to 2.4 +/- 2.1 pmol/liter (P < 0.01).
Copeptin shows identical changes during disordered water states as previously shown for AVP. It might be a reliable marker of AVP secretion and substitute for the measurement of circulating AVP levels in clinical routine.
精氨酸加压素（AVP）的测量通常很麻烦，因为它不稳定且半衰期短。AVP是由一个更大的前体肽与更稳定的肽 copeptin 一起衍生而来。Copeptin 是血管加压素原的 C 末端部分，已被证明是一种有用的工具，可用于指示危重病患者的 AVP 浓度。
本研究的目的是评估 copeptin 作为血容量和血浆渗透压紊乱状态下新标志物的临床实用性。
这是一项在大学医院进行的前瞻性观察性研究。
在24名健康成年人中使用三种技术及各自的对照研究来改变血浆渗透压和/或血容量：1）28小时禁水；2）17小时高渗盐水输注并伴有口渴；3）在自由饮水期间静脉注射去氨加压素的同时输注低渗盐水。
禁水导致体重减轻1.7kg，血浆渗透压升高至294.8±4.3mOsmol/kg，copeptin 从4.6±1.7pmol/L 增加至9.2±5.2pmol/L（P<0.0001）。在高渗盐水输注和口渴期间，血浆渗透压升高至296.1±3.4mOsmol/kg，copeptin 从4.9±3.0pmol/L 增加至19.9±4.8pmol/L（P<0.0001）。相反，在低渗盐水输注期间，血浆渗透压降至271.3±4.1mOsmol/kg，copeptin 从6.2±2.4pmol/L 降至2.4±2.1pmol/L（P<0.01）。
Copeptin 在水紊乱状态下的变化与先前 AVP 的变化相同。它可能是 AVP 分泌的可靠标志物，可在临床常规中替代循环 AVP 水平的测量。
