Ghigo E, Arvat E, Nicolosi M, Bellone J, Valetto M R, Mazza E, Imperiale E, Procopio M, Ghigo M C, Camanni F
Department of Clinical Physiopathology, University of Turin, Italy.
J Clin Endocrinol Metab. 1990 Aug;71(2):433-5. doi: 10.1210/jcem-71-2-433.
It has been shown that alpha 2-adrenoreceptor activation induced by clonidine (CLON) increases plasma GH levels in both adults and children. In this study the effects of CLON (150 micrograms/m2, orally) on GH secretion were studied both in the morning (from 0800-1100 h) and at night (from 2300-0200 h) in nine short children previously shown to have normal spontaneous nocturnal GH secretion. In the morning, CLON induced a GH increase higher than placebo [peak (mean +/- SEM), 23.8 +/- 4.3 vs. 3.4 +/- 1.4 micrograms/L; P = 0.0001; area under curve (AUC), 624.4 +/- 62.7 vs. 135.6 +/- 33.3 micrograms/L.h; P less than 0.00001]. In the night, no difference was observed between GH secretion after CLON (peak, 15.4 +/- 3.2 micrograms/L; AUC, 562.2 +/- 57.5 micrograms/L.h) and placebo (peak, 13.1 +/- 4.7 micrograms/L; AUC, 497.2 +/- 83.5 micrograms/L.h). Spontaneous GH secretion was higher during the night than in the morning (P = 0.0001), whereas nocturnal GH secretion overlapped with that in the morning after CLON. The data presented show that alpha 2-adrenoreceptor activation is probably mediated by increased endogenous GHRH release; our results suggest that the endogenous GHRH secretion is maximally stimulated at night.
已表明，可乐定（CLON）诱导的α2 - 肾上腺素能受体激活可增加成人和儿童的血浆生长激素（GH）水平。在本研究中，对9名先前显示夜间GH自然分泌正常的身材矮小儿童，研究了早晨（08:00 - 11:00）和夜间（23:00 - 02:00）口服CLON（150微克/平方米）对GH分泌的影响。早晨，CLON诱导的GH升高高于安慰剂[峰值（均值±标准误），23.8±4.3对3.4±1.4微克/升；P = 0.0001；曲线下面积（AUC），624.4±62.7对135.6±33.3微克/升·小时；P＜0.00001]。夜间，CLON后GH分泌（峰值，15.4±3.2微克/升；AUC，562.2±57.5微克/升·小时）与安慰剂（峰值，13.1±4.7微克/升；AUC，497.2±83.5微克/升·小时）之间未观察到差异。夜间的自发GH分泌高于早晨（P = 0.0001），而CLON后夜间GH分泌与早晨重叠。所呈现的数据表明，α2 - 肾上腺素能受体激活可能是由内源性生长激素释放激素（GHRH）释放增加介导的；我们的结果表明，内源性GHRH分泌在夜间受到最大刺激。
