Department of Veterinary Physiology, Veterinary Medical Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Neuroendocrinology. 2010;91(4):308-17. doi: 10.1159/000279311. Epub 2010 May 7.
BACKGROUND/AIMS: Growth hormone (GH) is secreted in pulsatile fashion, but the involvement of neuropeptides in the generation of GH pulses is not fully understood. The present study was conducted to elucidate the relationship between GH pulses and neuropeptide levels in the cerebrospinal fluid (CSF) of the third ventricle in ovariectomized goats.
CSF and plasma samples were collected every 15 min. Levels of plasma GH and profiles of GH-releasing hormone (GHRH), somatostatin (SRIH) and neuropeptide Y (NPY) in the CSF were measured by radioimmunoassay. Pulse/trough characteristics and correlations were assessed by the ULTRA algorithm, cross-correlation analysis and approximate entropy test.
The periodicity of GH pulses was 2.20 h. Although most GH pulses were associated with GHRH peaks, there was no correlation between GH and GHRH or GH and SRIH. NPY levels in the CSF fluctuated episodically at 2.03-hour intervals. GH pulse peaks occurred 0-30 min after NPY troughs, and there was a significant negative cross-correlation and negative synchronicity between GH and NPY profiles. In addition, intracerobroventricular infusion of NPY suppressed GH secretagogue (KP102)-induced GH release.
The periodic decrease in NPY may be involved in the generation of GH pulsatility in goats.
背景/目的：生长激素（GH）呈脉冲式分泌，但神经肽在 GH 脉冲产生中的作用尚不完全清楚。本研究旨在阐明去卵巢山羊第三脑室脑脊液（CSF）中 GH 脉冲与神经肽水平之间的关系。
每隔 15 分钟采集一次 CSF 和血浆样本。采用放射免疫法测定血浆 GH 水平和 CSF 中生长激素释放激素（GHRH）、生长抑素（SRIH）和神经肽 Y（NPY）的水平。采用 ULTRA 算法、互相关分析和近似熵测试评估脉冲/波谷特征和相关性。
GH 脉冲的周期性为 2.20 小时。尽管大多数 GH 脉冲与 GHRH 峰相关，但 GH 与 GHRH 或 GH 与 SRIH 之间没有相关性。CSF 中的 NPY 水平呈 2.03 小时间隔的周期性波动。GH 脉冲峰出现在 NPY 波谷后 0-30 分钟，GH 和 NPY 图谱之间存在显著的负互相关和负同步性。此外，脑室内输注 NPY 抑制了 KP102 诱导的 GH 释放。
NPY 的周期性减少可能参与了山羊 GH 脉冲性的产生。
