Endocr Pract. 2018 Mar;24(3):288-293. doi: 10.4158/EP-2017-0132.
The total cortisol (TC) response may be measured during the glucagon stimulation test (GST) for growth hormone (GH) reserve in order to assess the integrity of the hypothalamic-pituitary-adrenal (HPA) axis. Measurements of TC are unreliable in conditions of albumin and cortisol-binding globulin (CBG) alterations (e.g., hypoproteinemia or CBG deficiency). We aimed to measure the serum free cortisol (sFC) response to the GST in children and adolescents and determine whether it could predict the GH response to glucagon stimulation.
Infants and children with either short stature or growth attenuation who were referred for evaluation of GH reserve underwent the GST.
The study population consisted of 103 subjects (62 females), median age 3.9 years (range, 0.5-14). The mean basal and peak TC levels were 13.3 ± 6.7 μg/dL and 29.6 ± 8.8 μg/dL, respectively. The mean basal and peak sFC levels were 0.7 ± 0.8 μg/dL and 1.7 ± 1.1 μg/dL, respectively. There was a negative correlation between peak TC and age ( r = -0.3, P = .007) but not between peak sFC and age ( r = -0.09, P = .36). Ninety-five percent of the patients had peak TC levels >15.8 μg/dL and peak sFC levels >0.6 μg/dL.
Our results on a cohort of healthy short-statured children can serve as reference values for the sFC response during GST. Based on these results, we propose peak TC levels >15.8 μg/dL and peak sFC levels >0.6 μg/dL for defining normalcy of the HPA axis during the GST in children and adolescents.
ACTH = adrenocorticotrophic hormone BMI = body mass index CBG = cortisol-binding globulin GH = growth hormone GST = glucagon stimulation test HPA = hypothalamic-pituitary-adrenal SDS = standard deviation score sFC = serum free cortisol TC = total cortisol.
为了评估下丘脑-垂体-肾上腺（HPA）轴的完整性，在生长激素（GH）储备的胰高血糖素刺激试验（GST）期间可以测量总皮质醇（TC）的反应。在白蛋白和皮质醇结合球蛋白（CBG）改变（例如低蛋白血症或 CBG 缺乏）的情况下，TC 的测量是不可靠的。我们旨在测量儿童和青少年对 GST 的血清游离皮质醇（sFC）反应，并确定其是否可以预测胰高血糖素刺激对 GH 的反应。
因 GH 储备评估而转介的身材矮小或生长减弱的婴儿和儿童接受了 GST。
研究人群包括 103 名受试者（62 名女性），中位年龄为 3.9 岁（范围，0.5-14 岁）。基础和峰值 TC 水平的平均值分别为 13.3±6.7μg/dL 和 29.6±8.8μg/dL。基础和峰值 sFC 水平的平均值分别为 0.7±0.8μg/dL 和 1.7±1.1μg/dL。峰值 TC 与年龄呈负相关（r=-0.3，P=0.007），但峰值 sFC 与年龄无相关性（r=-0.09，P=0.36）。95%的患者的峰值 TC 水平>15.8μg/dL，峰值 sFC 水平>0.6μg/dL。
我们在一组健康的身材矮小儿童中的研究结果可以作为 GST 期间 sFC 反应的参考值。基于这些结果，我们建议在儿童和青少年的 GST 期间，将峰值 TC 水平>15.8μg/dL 和峰值 sFC 水平>0.6μg/dL 定义为 HPA 轴正常。
ACTH = 促肾上腺皮质激素；BMI = 体重指数；CBG = 皮质醇结合球蛋白；GH = 生长激素；GST = 胰高血糖素刺激试验；HPA = 下丘脑-垂体-肾上腺；SDS = 标准偏差分数；sFC = 血清游离皮质醇；TC = 总皮质醇。
