Tzanela M, Guyda H, Van Vliet G, Tannenbaum G S
Department of Pediatrics, McGill University, Montreal, Quebec, Canada.
J Clin Endocrinol Metab. 1996 Jul;81(7):2487-94. doi: 10.1210/jcem.81.7.8675565.
Despite the availability of numerous testing procedures to evaluate GH secretion in short children, there is still controversy about the most reliable test in the diagnosis of GH deficiency. We have recently demonstrated that in normal short children, priming with the long-acting somatostatin analog. SMS 201-995 (SMS), significantly potentiates their GH response to subsequent GHRH challenge. In the present study, we used the combined SMS + GHRH test in patients with GH deficiency to validate the hypothesis that this test would better discriminate between normal short children and those with truly diminished GH secretion. We studied 24 children classified into three groups according to their GH peak response to up to four conventional tests: 1) children with normal short stature and normal GH response (NSSA: GH peak > or = 10 micrograms/L, n = 6); 2) children with normal short stature with borderline GH response (NSSB: GH peak > or = 7 micrograms/L but < 10 micrograms/L, n = 4); and 3) GH-deficient children (GHD: GH peak < 7 micrograms/L, n = 14). Two study protocols were performed in all subjects: SMS (1 microgram/kg, sc) was randomly administered or omitted (control test) a 0800 h and GHRH (1 microgram/kg, iv) was given 5 h later. Plasma GH levels were measured every 30 min from 0800 h until 2 h after the GHRH injection. Pretreatment with SMS significantly augmented the GH peak response and the GH area under the GH concentration curve over 2 h after GHRH injection in the NSSA group, compared with control tests, but had no effect in the other two groups. While there was wide overlap of individual peak GH values to both the conventional tests and to the GHRH injection in the control test among the three groups of children, pretreatment with SMS resulted in complete discrimination between GHD and normal short children; the mean GH peak response to GHRH after SMS pretreatment was 8- to 9-fold lower in the GHD subjects (5.2 +/- 0.8 micrograms/L) compared with both the NSSA (44.0 +/- 14.3 micrograms/L; P < 0.01) and NSSB (42.9 +/- 5.0 micrograms/L; P < 0.01) groups and, more importantly, there was no overlap in the individual GH responses between GHD and normal short children. These results demonstrate that the combined SMS + GHRH test clearly discriminates normal short children from those with GHD. In view of its testing economy, safety, and accuracy, this combined test could become the test of choice to establish a diagnosis of GH deficiency in the slowly growing child.
尽管有多种检测程序可用于评估身材矮小儿童的生长激素（GH）分泌情况，但在GH缺乏症的诊断中，关于最可靠的检测方法仍存在争议。我们最近证明，对于正常身材矮小的儿童，使用长效生长抑素类似物SMS 201-995（SMS）进行预处理，可显著增强他们随后对生长激素释放激素（GHRH）激发试验的GH反应。在本研究中，我们对GH缺乏症患者使用了SMS + GHRH联合试验，以验证该试验能更好地区分正常身材矮小儿童和真正GH分泌减少儿童的假设。我们根据24名儿童对多达四项传统检测的GH峰值反应将其分为三组：1）身材正常矮小且GH反应正常的儿童（NSSA：GH峰值≥10μg/L，n = 6）；2）身材正常矮小但GH反应临界的儿童（NSSB：GH峰值≥7μg/L但＜10μg/L，n = 4）；3）GH缺乏症儿童（GHD：GH峰值＜7μg/L，n = 14）。对所有受试者进行了两种研究方案：上午8点随机给予SMS（1μg/kg，皮下注射）或不给予（对照试验），5小时后给予GHRH（1μg/kg，静脉注射）。从上午8点到GHRH注射后2小时，每30分钟测量一次血浆GH水平。与对照试验相比，SMS预处理显著增强了NSSA组在GHRH注射后2小时内的GH峰值反应以及GH浓度曲线下的GH面积，但对其他两组没有影响。虽然三组儿童在对照试验中，个体GH峰值对传统检测和GHRH注射的反应有很大重叠，但SMS预处理导致GHD儿童与正常身材矮小儿童完全区分开来；与NSSA组（44.0±14.3μg/L；P＜0.01）和NSSB组（42.9±5.0μg/L；P＜0.01）相比，GHD受试者在SMS预处理后对GHRH的平均GH峰值反应低8至9倍（5.2±0.8μg/L），更重要的是，GHD儿童与正常身材矮小儿童的个体GH反应没有重叠。这些结果表明，SMS + GHRH联合试验能清楚地区分正常身材矮小儿童和GHD儿童。鉴于其检测经济性、安全性和准确性，这种联合试验可能成为诊断生长缓慢儿童GH缺乏症的首选检测方法。
