Hilczer Maciej, Smyczynska Joahna, Stawerska Renata, Lewinski Andrej
Department of Endocrinology and Metabolic Diseases, Medical University of Lodz, Polish Mother's Memorial Hospital - Research Institute, Lodz, Poland.
Endocr Regul. 2006 Jun;40(2):37-45.
Growth hormone (GH) secretion is routinely assessed in provocative tests. However, some limitations of these tests have been reported, including a weak correlation between spontaneous GH secretion and GH peak in stimulating tests, poor reproducibility of test results and normalisation of previously decreased GH response to stimulation in the repeated provocative tests. The observed discrepancies between the results of consecutive GH stimulating tests in the same patient may be explained either by real changes in GH secretion or by the poor reproducibility of GH response to stimulation. Normalisation of previously decreased GH secretion should entail the increase of insulin-like growth factor-I (IGF-I) concentration, while stability of IGF-I secretion despite divergent GH response to stimulation in repeated tests might indicate the poor reproducibility of GH stimulating tests. continue with The aim of the study was a comparison of GH peak in repeated stimulating tests and of corresponding, simultaneously measured IGF-I concentration.
The investigation comprised 84 children with short stature who underwent repeated GH tests and IGF-I evaluation. In 60 patients each of two different tests (with clonidine and with glucagon, in standard doses) was performed twice, together with IGF-I measurement during both evaluations. In 20 patients (remaining in the same pubertal stage during the time period between the procedures in question) at least one test, together with IGF-I measurement, was repeated within one year.
The correlation between the results of GH tests, repeated during the two evaluations, was weak (r=0.22, p<0.05 for all patients and r=0.25, p<0.05 for the patients examined 2 times within 1 year), with the high within-subject variability (43.4 % and 59.5 %, respectively). Conversely, the correlation between two values of IGF-I SDS was good both for all patients (r=0.65, p<0.05) and especially for the patients examined twice within 1 year (r=0.96, p<0.05), with low within-subject variability for the latter subgroup of patients (11.2 %). The same GH stimulating tests, performed twice in the same patient, led to different conclusions (either the confirmation of GHD diagnosis or its exclusion) in most of examined patients. Poor reproducibility of GH stimulating tests, rather than the possibility of short-term changes in GH secretion, was confirmed.
生长激素（GH）分泌通常在激发试验中进行评估。然而，这些试验存在一些局限性，包括自发GH分泌与刺激试验中GH峰值之间的相关性较弱、试验结果的可重复性差以及在重复激发试验中先前降低的GH对刺激的反应恢复正常。同一患者连续GH刺激试验结果之间观察到的差异，可能是由于GH分泌的实际变化，也可能是由于GH对刺激反应的可重复性差。先前降低的GH分泌恢复正常应伴随着胰岛素样生长因子-I（IGF-I）浓度的升高，而在重复试验中尽管GH对刺激的反应不同，但IGF-I分泌稳定，这可能表明GH刺激试验的可重复性差。本研究的目的是比较重复刺激试验中的GH峰值以及相应的同时测量的IGF-I浓度。
该研究纳入了84名身材矮小的儿童，他们接受了重复的GH试验和IGF-I评估。60名患者分别进行了两种不同的试验（使用标准剂量的可乐定和胰高血糖素），每种试验均进行两次，并在两次评估期间同时测量IGF-I。20名患者（在相关程序之间的时间段内处于相同的青春期阶段）在一年内至少重复进行了一次试验并同时测量了IGF-I。
两次评估期间重复进行的GH试验结果之间的相关性较弱（所有患者r = 0.22，p < 0.05；一年内接受两次检查的患者r = 0.25，p < 0.05），受试者内变异性较高（分别为43.4%和59.5%）。相反，所有患者的IGF-I SDS的两个值之间的相关性良好（r = 0.65，p < 0.05），尤其是一年内接受两次检查的患者（r = 0.96，p < 0.05），后一组患者的受试者内变异性较低（11.2%）。同一患者进行两次相同的GH刺激试验，在大多数检查患者中得出了不同的结论（要么确认生长激素缺乏症诊断，要么排除该诊断）。证实了GH刺激试验的可重复性差，而非GH分泌短期变化的可能性。
