Bellone J, Valetto M R, Aimaretti G, Segni M, Volta C, Cardimale G, Baffoni C, Pasquino A M, Bernasconi S, Bartolotta E, Mucci M, Ghigo E
Department of Internal Medicine, University of Turin, Italy.
J Pediatr Endocrinol Metab. 1996 Sep-Oct;9(5):523-31. doi: 10.1515/jpem.1996.9.5.523.
Of the amino acids arginine is the most potent GH secretagogue in man. It potentiates the GH response to GHRH, exerts a weaker PRL-releasing effect, stimulates insulin and glucagon and induces a biphasic glucose variation. The potency and effects of other amino acids on pituitary and pancreatic hormones need to be clarified. In 43 children with normal short stature (5.3-14.0 yr; 30 M and 13 F) the effects of the infusion of phenylalanine (Phe, 0.08 g/kg), histidine (His, 0.1 g/kg), and leucine (Leu, 0.08 g/kg) on basal and GHRH-stimulated GH secretion and on PRL, insulin and glucose levels were studied and compared with those of arginine at high (hArg, 0.5 g/kg) or low dose (lArg, 0.2 g/kg). Phe increased basal (p < 0.05) but not GHRH-stimulated GH levels, induced PRL and insulin rises (p < 0.03 and p < 0.03), and did not change glycemia. Though a trend toward an increase in basal GH levels was found after His, His and Leu did not significantly modify either basal or GHRH-induced GH secretion nor basal PRL, insulin and glucose levels. Both hArg and lArg increased basal (p < 0.0001 and p < 0.05, respectively) and GHRH-stimulated GH levels (p < 0.006 and p < 0.006). hArg increased both PRL (p < 0.002) and insulin levels (p < 0.005) more (p < 0.0005 and p < 0.004) than lArg (p < 0.005 and p < 0.005), while glucose levels showed a similar increase followed by a similar decrease. We conclude that in childhood: a) Phe significantly increases GH secretion but, differently from Arg, does not potentiate the response to GHRH, suggesting different mechanisms of action of these amino acids; b) differently from His and Leu, Phe is a PRL and insulin secretagogue but is less potent than Arg; c) Arg has the highest stimulatory effect on pituitary and pancreatic hormones.
在人体的氨基酸中，精氨酸是最有效的生长激素促分泌素。它能增强生长激素对生长激素释放激素（GHRH）的反应，具有较弱的催乳素释放作用，刺激胰岛素和胰高血糖素，并引起双相性血糖变化。其他氨基酸对垂体和胰腺激素的作用强度及效果尚待阐明。在43名身材正常但矮小的儿童（年龄5.3 - 14.0岁；男30名，女13名）中，研究了输注苯丙氨酸（Phe，0.08 g/kg）、组氨酸（His，0.1 g/kg）和亮氨酸（Leu，0.08 g/kg）对基础状态及GHRH刺激后的生长激素分泌以及催乳素、胰岛素和血糖水平的影响，并与高剂量（hArg，0.5 g/kg）或低剂量（lArg，0.2 g/kg）精氨酸的作用进行比较。苯丙氨酸可增加基础状态下的生长激素水平（p < 0.05），但对GHRH刺激后的生长激素水平无影响，可引起催乳素和胰岛素升高（p < 0.03和p < 0.03），且不改变血糖水平。虽然组氨酸输注后基础生长激素水平有升高趋势，但组氨酸和亮氨酸对基础状态或GHRH诱导的生长激素分泌以及基础催乳素、胰岛素和血糖水平均无显著影响。高剂量精氨酸和低剂量精氨酸均可增加基础状态下的生长激素水平（分别为p < 0.0001和p < 0.05）以及GHRH刺激后的生长激素水平（p < 0.006和p < 0.006）。高剂量精氨酸比低剂量精氨酸更能增加催乳素（p < 0.002）和胰岛素水平（p < 0.005）（分别为p < 0.0005和p < 0.004对比p < 0.005和p < 0.005），而血糖水平呈现相似的先升高后降低。我们得出结论，在儿童期：a）苯丙氨酸可显著增加生长激素分泌，但与精氨酸不同，它不能增强对GHRH的反应，提示这些氨基酸的作用机制不同；b）与组氨酸和亮氨酸不同，苯丙氨酸是一种催乳素和胰岛素促分泌素，但效力低于精氨酸；c）精氨酸对垂体和胰腺激素具有最高的刺激作用。
