Davis T M, Burrin J M, Bloom S R
Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom.
J Clin Endocrinol Metab. 1987 Dec;65(6):1248-52. doi: 10.1210/jcem-65-6-1248.
The effect of GHRH in a dose (120 micrograms) thought to produce a maximal GH response was compared with the GH response to insulin-induced hypoglycemia, iv infusion of the hypothalamic neuropeptide galanin (40 pmol/kg.min for 40 min), and a combination of GHRH and galanin in normal men. The median peak serum GH level was 29 mU/L in response to GHRH, 28.9 mU/L in response to insulin hypoglycemia, 17.3 mU/L in response to galanin, and 115.0 mU/L in response to the combination of galanin and GHRH. GH release induced by galanin was completely inhibited by a concomitant somatostatin infusion (50 pmol/kg.min). Thus, galanin increased the peak GH response to GHRH, previously thought to be one of the most powerful stimulants to GH release, more than 3-fold. Since the dose of GHRH used was thought to be maximal and since galanin is reported not to have direct effects on the pituitary, one possible mode of action of galanin would be inhibition of tonic endogenous hypothalamic somatostatin release.
在正常男性中，将生长激素释放激素（GHRH）在被认为可产生最大生长激素（GH）反应的剂量（120微克）下所产生的效应，与GH对胰岛素诱导的低血糖、静脉输注下丘脑神经肽甘丙肽（40皮摩尔/千克·分钟，持续40分钟）以及GHRH与甘丙肽联合使用时的反应进行了比较。对GHRH反应的血清GH峰值中位数为29 mU/L，对胰岛素低血糖反应为28.9 mU/L，对甘丙肽反应为17.3 mU/L，对甘丙肽与GHRH联合使用反应为115.0 mU/L。同时输注生长抑素（50皮摩尔/千克·分钟）可完全抑制甘丙肽诱导的GH释放。因此，甘丙肽使此前被认为是最强有力的GH释放刺激物之一的GHRH的峰值GH反应增加了3倍多。由于所用的GHRH剂量被认为是最大剂量，且据报道甘丙肽对垂体没有直接作用，甘丙肽的一种可能作用方式可能是抑制内源性下丘脑生长抑素的持续释放。
