Department of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland.
Department of Clinical Research, University of Basel, Basel, Switzerland.
Eur J Endocrinol. 2021 Aug 3;185(3):355-364. doi: 10.1530/EJE-21-0346.
Oxytocin, secreted into circulation through the posterior pituitary, regulates lactation, weight, and socio-behavioral functioning. Oxytocin deficiency has been suggested in patients with hypopituitarism; however, diagnostic testing for oxytocin deficiency has not been developed. The aim of this study was to investigate known pituitary provocation tests to stimulate plasma oxytocin.
Sixty-five healthy volunteers underwent either the hypertonic saline or arginine infusion test, known to stimulate copeptin, or the oral macimorelin test, known to stimulate growth hormone. Plasma oxytocin was measured before and once plasma sodium level ≥ 150 mmol/L for the hypertonic saline, after 60 min for the arginine infusion, and after 45 min for the oral macimorelin test (expected peak of copeptin and growth hormone levels, respectively). Primary outcome was a change from basal to stimulated oxytocin levels using paired t-tests.
As expected, copeptin increased in response to hypertonic saline and arginine infusion (P < 0.001), and growth hormone increased to oral macimorelin (P < 0.001). Oxytocin increased in response to hypertonic saline infusion from 0.4 (0.2) to 0.6 pg/mL (0.3) (P = 0.003) but with a high variance. There was no change to arginine infusion (P = 0.4), and a trend to lower stimulated levels to oral macimorelin (P = 0.05).
Neither the arginine infusion nor the oral macimorelin test stimulates plasma oxytocin levels, whereas there was an increase with high variance upon hypertonic saline infusion. As a predictable rise in most participants is required for a reliable pituitary provocation test, none of the investigated pituitary provocation tests can be recommended diagnostically to identify patients with an oxytocin deficiency.
通过垂体后叶分泌到循环系统中的催产素，调节泌乳、体重和社会行为功能。有人认为，垂体功能减退症患者存在催产素缺乏，但尚未开发出用于诊断催产素缺乏症的检测方法。本研究旨在探讨已知的刺激血浆催产素的垂体刺激试验。
65 名健康志愿者接受高渗盐水或精氨酸输注试验，已知这两种试验可刺激 copeptin；或口服麦角硫因试验，已知可刺激生长激素。在高渗盐水时，当血浆钠离子浓度≥150mmol/L 时，在精氨酸输注后 60 分钟，以及口服麦角硫因试验后 45 分钟时（分别为 copeptin 和生长激素水平的预期峰值）测量血浆催产素。主要结果是使用配对 t 检验比较基础值和刺激后的催产素水平的变化。
如预期的那样，高渗盐水和精氨酸输注会引起 copeptin 增加（P < 0.001），而口服麦角硫因会引起生长激素增加（P < 0.001）。高渗盐水输注后，催产素从 0.4（0.2）pg/mL 增加到 0.6 pg/mL（0.3）（P = 0.003），但变化幅度较大。精氨酸输注后催产素无变化（P = 0.4），而口服麦角硫因试验后催产素水平呈下降趋势（P = 0.05）。
精氨酸输注和口服麦角硫因试验均不能刺激血浆催产素水平，而高渗盐水输注后催产素水平升高，但幅度较大。由于可靠的垂体刺激试验需要大多数参与者有可预测的升高，因此，目前尚无任何一种已研究的垂体刺激试验可用于诊断性地识别存在催产素缺乏症的患者。
