Maghnie M, Spica-Russotto V, Cappa M, Autelli M, Tinelli C, Civolani P, Deghenghi R, Severi F, Loche S
Clinica Pediatrica, Policlinico S. Matteo, Universitá di Pavia, Italy.
J Clin Endocrinol Metab. 1998 Nov;83(11):3886-9. doi: 10.1210/jcem.83.11.5242.
We evaluated the GH-releasing effect of hexarelin (Hex; 2 microg/kg, i.v.) and GHRH (1 microg/kg, i.v.) in 18 patients (11 males and 7 females, aged 2.5-20.4 yr) with GH deficiency (GHD) whose hypothalamic pituitary abnormalities had been previously characterized by dynamic magnetic resonance imaging (MRI). Ten patients had isolated GHD, and 8 had multiple pituitary hormone deficiency. All patients were receiving appropriate hormone replacement therapy. Twenty-four prepubertal short normal children (11 boys and 13 girls, aged 5.9-13 yr, body weight within +/-10% of ideal weight) served as controls. MRI studies revealed an ectopic posterior pituitary at the infundibular recess in all patients. A residual vascular component of the pituitary stalk was visualized in 8 patients with isolated GHD (group 1), whereas MRI showed the absence of the pituitary stalk (vascular and neural components) in the remaining 10 patients (group 2), of whom 8 had multiple pituitary hormone deficiency and 2 had isolated GHD. In the short normal children, the mean peak GH response to GHRH (24.8 +/- 4.4 microg/L) was significantly lower than that observed after Hex treatment (48.1 +/- 4.9 microg/L; P < 0.0001). In the GHD patients of group 2, the mean peak GH responses to GHRH (1.4 +/- 0.3 microg/L) and Hex (0.9 +/- 0.3 microg/L) were similar and markedly low. In the patients of group 1, the GH responses to GHRH (8.7 +/- 1.3 microg/L) and Hex (7.0 +/- 1.3 microg/L) were also similar, but were significantly higher that those observed in group 2 (P < 0.0001). In the whole group of patients, a significant correlation was found between the GH peaks after Hex and those after GHRH (r = 0.746; P < 0.0001). In this study we have confirmed that the integrity of the hypothalamic pituitary connections is essential for Hex to express its full GH-releasing activity and that Hex is able to stimulate GH secretion in patients with GHD but with a residual vascular component of the pituitary stalk.
我们评估了六肽生长激素释放肽（Hex；2微克/千克，静脉注射）和生长激素释放激素（GHRH；1微克/千克，静脉注射）对18例生长激素缺乏症（GHD）患者（11例男性，7例女性，年龄2.5 - 20.4岁）的生长激素释放作用，这些患者的下丘脑 - 垂体异常先前已通过动态磁共振成像（MRI）进行了特征描述。10例患者为孤立性生长激素缺乏症，8例患者为多种垂体激素缺乏症。所有患者均接受适当的激素替代治疗。24例青春期前身材正常的儿童（11例男孩和13例女孩，年龄5.9 - 13岁，体重在理想体重的±10%范围内）作为对照。MRI研究显示所有患者在漏斗隐窝处均有异位垂体后叶。8例孤立性生长激素缺乏症患者（第1组）可见垂体柄的残余血管成分，而MRI显示其余10例患者（第2组）垂体柄（血管和神经成分）缺失，其中8例为多种垂体激素缺乏症，2例为孤立性生长激素缺乏症。在身材正常的儿童中，对GHRH的平均生长激素峰值反应（24.8±4.4微克/升）显著低于六肽生长激素释放肽治疗后观察到的反应（48.1±4.9微克/升；P < 0.0001）。在第2组的生长激素缺乏症患者中，对GHRH（1.4±0.3微克/升）和六肽生长激素释放肽（0.9±0.3微克/升）的平均生长激素峰值反应相似且明显较低。在第1组患者中，对GHRH（8.7±1.3微克/升）和六肽生长激素释放肽（7.0±1.3微克/升）的生长激素反应也相似，但显著高于第2组观察到的反应（P < 0.0001）。在整个患者组中，六肽生长激素释放肽后的生长激素峰值与GHRH后的生长激素峰值之间存在显著相关性（r = 0.746；P < 0.0001）。在本研究中，我们证实下丘脑 - 垂体连接的完整性对于六肽生长激素释放肽发挥其全部生长激素释放活性至关重要，并且六肽生长激素释放肽能够刺激生长激素缺乏症但垂体柄有残余血管成分患者的生长激素分泌。
