Sakellaris P C, Vernikos-Danellis J
Endocrinology. 1975 Sep;97(3):597-602. doi: 10.1210/endo-97-3-597.
The response and adaptation of the pituitary-adrenal system to chronic stresses was investigated. These included individual caging, confinement, and exposure to cold for varying periods of time. Studies were carried out demonstrating that during the period of adaptation when plasma corticosterone concentrations returned toward their prestress level despite continued exposure to the stressor, the animals responded to additional stimuli of ether for 1 min, a saline injection, or release from confinement with a faster increase (within 2.5 min) in plasma corticosterone than controls (10 min). This increased responsiveness was not limited to the adrenal since plasma ACTH showed a greater increase 2.5 min after ether in animals confined for 40 min than in nonconfined rats. It is concluded that during adaptation to a chronic stress the pituitary-adrenal system is not inhibited by the circulating steroid level but is actually hypersensitive to additional stimuli. Thus, chronic stress may cause an increased drive to the ACTH-secreting mechanism which compensates or overrides the cortical feedback.
研究了垂体 - 肾上腺系统对慢性应激的反应和适应性。这些慢性应激包括个体单独饲养、限制活动以及在不同时间段暴露于寒冷环境。研究表明，在适应期，尽管持续暴露于应激源，但血浆皮质酮浓度恢复到应激前水平时，动物对乙醚刺激1分钟、注射生理盐水或从限制活动状态释放等额外刺激的反应是，血浆皮质酮比对照组更快升高（在2.5分钟内）（对照组为10分钟）。这种增强的反应性不仅限于肾上腺，因为在限制活动40分钟的动物中，乙醚刺激2.5分钟后血浆促肾上腺皮质激素（ACTH）的升高幅度比未限制活动的大鼠更大。结论是，在适应慢性应激期间，垂体 - 肾上腺系统不受循环类固醇水平的抑制，实际上对额外刺激高度敏感。因此，慢性应激可能导致促肾上腺皮质激素分泌机制的驱动增加，从而补偿或超越皮质反馈。
