Ultradian corticosterone secretion is maintained in the absence of circadian cues.
Ultradian corticosterone secretion is maintained in the absence of circadian cues.
复制标题
在没有昼夜节律提示的情况下，超昼夜皮质酮分泌得以维持。
DOI：
10.1111/j.1460-9568.2012.08213.x
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Waite EJ
中科院分区：
文献类型：
--
作者：
Waite EJ
血浆皮质酮水平表现出昼夜节律和超昼夜节律。这些节律的昼夜节律成分由视交叉上核（SCN）调节。我们的研究调查的重要性，SCN在调节超日节律。使用两种方法将大鼠的下丘脑-垂体-肾上腺（HPA）轴与正常昼夜节律输入分离：（i）暴露于恒定光（LL）环境和（ii）SCN的电解损伤。使用自动采样系统采集血样。正如预期的那样，两种治疗均导致皮质酮分泌的昼夜节律模式丧失。然而，所有动物在24小时内维持皮质酮的超昼夜脉动分泌。 此外，SCN输入的损失揭示了运动和HPA活动之间的潜在关系。在对照组（LD）大鼠中，ultradian自发活动和激素分泌之间没有明显的相关性，而在LL大鼠中，ultradian活动的发作始终遵循脉冲性激素分泌增加的时期。这些数据清楚地表明，皮质酮分泌的超昼夜节律是通过独立于SCN输入的机制产生的，支持了下丘脑脉冲发生器的最新证据。
Plasma levels of corticosterone exhibit both circadian and ultradian rhythms. The circadian component of these rhythms is regulated by the suprachiasmatic nucleus (SCN). Our studies investigate the importance of the SCN in regulating ultradian rhythmicity. Two approaches were used to dissociate the hypothalamic‐pituitary‐adrenal (HPA) axis from normal circadian input in rats: (i) exposure to a constant light (LL) environment and (ii) electrolytic lesioning of the SCN. Blood was sampled using an automated sampling system. As expected, both treatments resulted in a loss of the circadian pattern of corticosterone secretion. Ultradian pulsatile secretion of corticosterone however, was maintained across the 24 h in all animals. Furthermore, the loss of SCN input revealed an underlying relationship between locomotor and HPA activity. In control (LD) rats there was no clear correlation between ultradian locomotor activity and hormone secretion, whereas, in LL rats, episodes of ultradian activity were consistently followed by periods of increased pulsatile hormone secretion. These data clearly demonstrate that the ultradian rhythm of corticosterone secretion is generated through a mechanism independent of the SCN input, supporting recent evidence for a sub‐hypothalamic pulse generator.