Age-related changes in the diurnal rhythm of CRH gene expression in the paraventricular nuclei
Age-related changes in the diurnal rhythm of CRH gene expression in the paraventricular nuclei
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DOI：
10.1152/ajpendo.1996.270.2.e238
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发表时间：
1996-02-01
影响因子：
5.1
通讯作者：
Wise, PM
中科院分区：
文献类型：
--
作者：
Cai, AH;Wise, PM
促肾上腺皮质激素释放激素（CRH）的昼夜节律分泌被认为调节促肾上腺皮质激素和皮质酮的昼夜节律分泌模式。我们以前报道过17- 20岁大鼠血清皮质酮浓度的昼夜节律幅度下降。在本实验中，我们测试了在中年期间是否会发生与年龄相关的室室旁核（PVN）中CRH mRNA的日常节律和/或水平的改变。成群的年轻和中年动物在一天的几次被杀死。我们使用原位杂交技术评估了PVN和PVN背内侧分支中CRH mRNA的水平。在幼龄大鼠中，CRH mRNA的表达在PVN背内侧呈现昼夜节律。在整个内侧PVN中也观察到相同的趋势。在中年大鼠中，两个区域均未检测到节律。CRH mRNA的总体平均水平在这两个年龄组之间没有差异。这些发现表明，在衰老过程中，视交叉上核或其携带神经内分泌输出能力的变化发生得相对较早。
A circadian rhythm secretion of corticotropin-releasing hormone (CRH) is thought to regulate the circadian pattern of secretion of adrenocorticotropic hormone and corticosterone. We have previously reported that the amplitude of the diurnal rhythm of serum corticosterone concentrations decreases in 17- to 20-mo-old rats. In the present experiment, we tested whether an age-related alteration in the daily rhythm and/or level of CRH mRNA in the paraventricular nuclei (PVN) occurs during middle age. Groups of young and middle-aged animals were killed at several times of day. We assessed the level of CRH mRNA in the PVN and dorsal medial subdivision of the PVN using in situ hybridization. In young rats, CRH mRNA expression exhibited a diurnal rhythm in the dorsal medial PVN. The same trend was observed in the entire medial PVN. In middle-aged rats, no rhythm was detected in either region. The overall average level of CRH mRNA was not different between these two age groups. These findings suggest that changes in the suprachiasmatic nucleus or in its ability to entrain neuroendocrine outputs occur relatively early during the aging process.