Arvat E, Ghigo E, Nicolosi M, Boffano G M, Bellone J, Yin-Zhang W, Mazza E, Camanni F
Department of Clinical Physiopathology, University of Turin, Italy.
Clin Endocrinol (Oxf). 1992 Apr;36(4):347-50. doi: 10.1111/j.1365-2265.1992.tb01458.x.
To clarify the mechanism by which galanin, a 29-amino-acid peptide, increases GH secretion in man.
We studied the GH-releasing effect of this neurohormone (galanin, 15 micrograms/kg) infused over 60 minutes after 120 minutes of saline, following a previous GHRH bolus (GHRH 1 microgram/kg i.v. at 0 minutes, galanin infused from 120 to 180 minutes) and coadministered with the second of two consecutive GHRH boluses (GHRH every 120 minutes, galanin infused from 120 to 180 minutes).
Fourteen healthy male subjects, aged 20-34 years, in two groups (group A, 20-31 years (n = 8); group B, 25-34 years (n = 6)) were studied.
Blood samples were drawn every 15 minutes of 255 minutes. Serum GH was measured in duplicate by IRMA. Statistical analysis of the data was carried out by non-parametric ANOVA test.
The GH response to galanin infused 120 minutes after saline overlapped with that induced by the neuropeptide infused following previous GHRH bolus (AUC, mean +/- SEM: 317.3 +/- 73.2 vs 326.8 +/- 54.2 micrograms/l/h). The GH-releasing effect of the second GHRH bolus (126.9 +/- 32.3 micrograms/l/h) was lower than that of the first one (503.4 +/- 41.3 micrograms/l/h; P = 0.0002). Galanin markedly enhanced the GH responses to the second GHRH bolus (1118.0 +/- 212.7 micrograms/l/h; P = 0.0002 vs second GHRH bolus alone) so that it did not significantly differ from the first one (710.9 +/- 107.8 micrograms/l/h).
Our results show that the GH-releasing effect of galanin is not modified by GHRH pretreatment and that the neuropeptide reinstates the GH response to the repeated GHRH stimulation in man. They suggest that these effects are due to the inhibition of hypothalamic somatostatin release.
阐明含有29个氨基酸的肽类物质甘丙肽增加人体生长激素（GH）分泌的机制。
我们研究了这种神经激素（甘丙肽，15微克/千克）在输注生理盐水120分钟后持续输注60分钟的促生长激素释放作用，此前先给予一次生长激素释放激素（GHRH）推注（0分钟时静脉注射1微克/千克GHRH，120至180分钟输注甘丙肽），并与连续两次GHRH推注中的第二次同时给予（每120分钟一次GHRH，120至180分钟输注甘丙肽）。
14名年龄在20 - 34岁的健康男性受试者，分为两组（A组，20 - 31岁（n = 8）；B组，25 - 34岁（n = 6））进行研究。
在255分钟内每隔15分钟采集一次血样。采用免疫放射分析（IRMA）法对血清GH进行双份测定。数据的统计分析采用非参数方差分析检验。
在输注生理盐水120分钟后输注甘丙肽引起的GH反应与在先前GHRH推注后输注该神经肽引起的反应重叠（曲线下面积，平均值±标准误：317.3±73.2 vs 326.8±54.2微克/升/小时）。第二次GHRH推注的促生长激素释放作用（126.9±32.3微克/升/小时）低于第一次（503.4±41.3微克/升/小时；P = 0.0002）。甘丙肽显著增强了对第二次GHRH推注的GH反应（1118.0±212.7微克/升/小时；与单独第二次GHRH推注相比，P = 0.0002），使其与第一次推注的反应（710.9±107.8微克/升/小时）无显著差异。
我们的结果表明，甘丙肽的促生长激素释放作用不受GHRH预处理的影响，且该神经肽可恢复人体对重复GHRH刺激的GH反应。这些作用提示是由于下丘脑生长抑素释放受到抑制所致。
