Saito H, Hosoi E, Saito S
Department of Internal Medicine, Tokushima Teishin (Posts and Telecommunications) Hospital, Japan.
Horm Metab Res. 1997 Sep;29(9):422-6. doi: 10.1055/s-2007-979069.
To clarify the role of growth hormone-releasing hormone (GHRH) in the regulation of the episodic growth hormone (GH) secretion which is known to occur constantly in the initial slow wave stage of nocturnal sleep in man, we studied the relation between the secretions of plasma immunoreactive(IR)-GHRH and GH while recording electroencephalograms. In subjects who showed a normal sleep pattern, the plasma IR-GHRH level increased 3- to 4-fold just before the surge of plasma GH, suggesting that GH release in the initial slow wave stage of sleep is mainly mediated by GHRH. However, when there was an apparent GH surge just before the onset of sleep, the magnitude of the GH response associated with the initial slow wave stage tended to be blunted, even when sufficient IR-GHRH was released. We also observed no appreciable fluctuations of plasma IR-GHRH during nocturnal sleep in a patient diagnosed as having GH-deficient dwarfism, suggesting the primary lesion was on the hypothalamus level, not the pituitary, in such a patient. In a case of multiple endocrine neoplasia (MEN) type I with an ectopic (GHRH-producing pancreatic tumor, no remarkable elevation of plasma IR-GHRH was detected in the initial slow wave stage of nocturnal sleep. We conclude that the present study is significant not only in demonstrating the physiology of GHRH release, but also in establishing a safe, reliable and practical test for routine clinical use to investigate intrinsic ability to release GHRH and the primary lesions in patients with disorders of GH secretion.
为了阐明生长激素释放激素（GHRH）在调节阵发性生长激素（GH）分泌中的作用，已知这种分泌在人类夜间睡眠的初始慢波阶段持续发生，我们在记录脑电图的同时研究了血浆免疫反应性（IR）-GHRH和GH分泌之间的关系。在睡眠模式正常的受试者中，血浆IR-GHRH水平在血浆GH激增前增加3至4倍，这表明睡眠初始慢波阶段的GH释放主要由GHRH介导。然而，当在睡眠开始前有明显的GH激增时，即使释放了足够的IR-GHRH，与初始慢波阶段相关的GH反应幅度也往往会减弱。我们还观察到，在一名被诊断为生长激素缺乏性侏儒症的患者夜间睡眠期间，血浆IR-GHRH没有明显波动，这表明该患者的原发性病变位于下丘脑水平，而非垂体。在一例患有异位（产生GHRH的胰腺肿瘤）的多发性内分泌腺瘤（MEN）I型患者中，在夜间睡眠的初始慢波阶段未检测到血浆IR-GHRH有明显升高。我们得出结论，本研究不仅在证明GHRH释放的生理学方面具有重要意义，而且在建立一种安全、可靠且实用的常规临床检测方法以研究GHRH释放的内在能力以及生长激素分泌障碍患者的原发性病变方面也具有重要意义。
