Pombo M, Leal-Cerro A, Barreiro J, Peñalva A, Peino R, Mallo F, Dieguez C, Casanueva F F
Department of Pediatrics, University of Santiago de Compostela, Spain.
J Pediatr Endocrinol Metab. 1996 Jun;9 Suppl 3:333-8.
Pituitary GH reserve can be assessed by substances that act directly at the somatotroph, such as GHRH, or by a variety of metabolic and neuropharmacological tests acting at the hypothalamic level, such as hypoglycemia, clonidine or L-Dopa. In order to evaluate GHRP-6 as a test of pituitary GH reserve, we studied GH responses of i.v. administered GHRP-6 in a group of short-statured children, as well as in a group of adults diagnosed with growth hormone deficiency (GHD) by conventional GH testing. Although we found that the GH response to GHRP-6 was lower in patients with GHD than in normal children, on an individual basis a considerable degree of overlap was observed between the two groups. In contrast, we found an almost complete blockade of GH response to either GHRP-6 or GHRH plus GHRP-6 in patients with pituitary stalk transection, suggesting that this could be a cost-effective test for the diagnosis of this condition. A similar finding was also obtained in GH response to the combined administration of GHRH plus GHRP-6 in patients with GHD of adult onset; this test may well prove valuable in the diagnosis of this clinical entity.
垂体生长激素储备可以通过直接作用于生长激素细胞的物质来评估，如生长激素释放激素（GHRH），也可以通过作用于下丘脑水平的各种代谢和神经药理学试验来评估，如低血糖、可乐定或左旋多巴。为了评估生长激素释放肽-6（GHRP-6）作为垂体生长激素储备试验的价值，我们研究了静脉注射GHRP-6后一组身材矮小儿童以及一组通过传统生长激素检测诊断为生长激素缺乏症（GHD）的成年人的生长激素反应。尽管我们发现GHD患者对GHRP-6的生长激素反应低于正常儿童，但在个体水平上，两组之间存在相当程度的重叠。相比之下，我们发现垂体柄横断患者对GHRP-6或生长激素释放激素（GHRH）加GHRP-6的生长激素反应几乎完全被阻断，这表明这可能是诊断该疾病的一种经济有效的试验。在成年发病的GHD患者中，对GHRH加GHRP-6联合给药的生长激素反应也得到了类似的结果；该试验很可能在诊断这一临床实体方面具有价值。
