School of Biomedical Science, University of Queensland, Brisbane, Queensland 4072, Australia.
Endocrinology. 2011 Aug;152(8):3165-71. doi: 10.1210/en.2011-0253. Epub 2011 May 17.
Measures of pulsatile GH secretion require frequent collection and analysis of blood samples at regular intervals. Due to blood volume constraints, repeat measures of circulating levels of GH in mice remain challenging. Consequently, few observations exist in which the pulsatile pattern of GH secretion in mice have been characterized. To address this, we developed a technique for the collection and analysis of circulating levels of GH at regular and frequent intervals in freely moving mice. This was achieved through the development of a sensitive assay for the detection of GH in small (2 μl) quantities of whole blood. The specificity and accuracy of this assay was validated following guidelines established for single-laboratory validation as specified by the International Union of Pure and Applied Chemistry. We incorporated an established method for tail-clip blood sample collection to determine circulating levels of GH secretion in 36 whole blood samples collected consecutively over a period of 6 h. Resulting measures were characterized by peak secretion periods and interpulse stable baseline secretion periods. Periods characterized by elevated whole blood GH levels consisted of multicomponent peaks. Deconvolution analysis of resulting measures confirmed key parameters associated with pulsatile GH secretion. We show a striking decrease in pulsatile GH secretion in mice after 12-18 h of fasting. This model is necessary to characterize the pulsatile profile of GH secretion in mice and will significantly contribute to current attempts to clarify mechanisms that contribute to the regulation of GH secretion.
测定脉冲式 GH 分泌需要频繁采集和定期分析血液样本。由于血量限制，重复测量小鼠循环中 GH 水平仍然具有挑战性。因此，很少有关于描述小鼠 GH 分泌脉冲模式的观察结果。为了解决这个问题，我们开发了一种在自由活动的小鼠中定期、频繁采集和分析循环 GH 水平的技术。这是通过开发一种灵敏的检测方法来实现的，该方法可以检测小体积（2μl）全血中的 GH。该检测方法的特异性和准确性已根据国际纯粹与应用化学联合会（International Union of Pure and Applied Chemistry）规定的单实验室验证指南进行了验证。我们采用了一种已建立的尾夹采血方法，以确定在 6 小时连续采集的 36 个全血样本中的循环 GH 分泌水平。所得测量值的特征是有高峰分泌期和脉冲间隔稳定的基础分泌期。表现为升高的全血 GH 水平的时期由多成分峰组成。对所得测量值的解卷积分析证实了与脉冲式 GH 分泌相关的关键参数。我们发现，禁食 12-18 小时后，小鼠的脉冲式 GH 分泌明显减少。这种模型对于描述小鼠 GH 分泌的脉冲式特征是必要的，并且将极大地有助于目前阐明促进 GH 分泌调节的机制的尝试。
