Loche S, Colao A, Cappa M, Bellone J, Aimaretti G, Farello G, Faedda A, Lombardi G, Deghenghi R, Ghigo E
Servizio di Endocrinologia Pediatrica, Ospedale Regionale per le Microcitemie, Cagliari, Italy.
J Clin Endocrinol Metab. 1997 Mar;82(3):861-4. doi: 10.1210/jcem.82.3.3795.
We studied the variability of the GH response to the synthetic hexapeptide hexarelin (Hex) and the effect of sex steroids on the GH-releasing effect of Hex in a group of prepubertal short normal children. Twenty-five children were tested on two occasions 3-7 days apart with 2 micrograms/kg, i.v., Hex. The GH response to Hex was reevaluated after testosterone (T) administration in 10 boys, after ethinyl estradiol (EE) administration in 15 children (5 boys and 10 girls), and after oxandrolone (Ox) administration in 8 boys. In the 25 children tested twice, the mean GH peak and mean area under the curve after the first and second tests were similar. The mean (+/- SD) coefficients of variation of the GH peak and area under the curve responses to Hex was 22.7 +/- 21.0% and 24.0 +/- 20.7%, respectively. Priming with T and EE resulted in an increased GH response to Hex [41.8 +/- 21.0 before vs. 71.1 +/- 28.3 after T (P < 0.001); 43.0 +/- 14.5 before vs. 60.0 +/- 20.0 after EE (P < 0.005)], whereas Ox administration had no effect on the Hex-induced GH release. These data confirm that Hex is a potent stimulus for GH secretion in children with a limited intraindividual variability. In addition, we have shown that both T and EE, but not Ox, significantly augment the GH-releasing effect of Hex. Our data suggest that the sex steroid-induced increase in the GH response to Hex is mediated by estrogens.
我们研究了青春前期身材正常的矮小儿童对合成六肽生长激素释放肽（Hex）的生长激素（GH）反应变异性，以及性类固醇对Hex促生长激素释放作用的影响。25名儿童在间隔3 - 7天的两个时间点接受静脉注射2微克/千克的Hex测试。对10名男孩给予睾酮（T）后、15名儿童（5名男孩和10名女孩）给予炔雌醇（EE）后以及8名男孩给予氧雄龙（Ox）后，重新评估对Hex的GH反应。在接受两次测试的25名儿童中，第一次和第二次测试后的平均GH峰值和曲线下平均面积相似。对Hex反应的GH峰值和曲线下面积的平均（±标准差）变异系数分别为22.7±21.0%和24.0±20.7%。用T和EE预处理导致对Hex的GH反应增加[T处理前为41.8±21.0，处理后为71.1±28.3（P < 0.001）；EE处理前为43.0±14.5，处理后为60.0±20.0（P < 0.005）]，而给予Ox对Hex诱导的GH释放没有影响。这些数据证实，Hex是儿童生长激素分泌的有效刺激物，个体内变异性有限。此外，我们已经表明，T和EE均可显著增强Hex的促生长激素释放作用，但Ox无此作用。我们的数据表明，性类固醇诱导的对Hex的GH反应增加是由雌激素介导的。
