Scaccianoce S, Di Sciullo A, Angelucci L
Institute of Pharmacology, Medical Faculty, University La Sapienza, Rome, Italy.
Neuroendocrinology. 1990 Aug;52(2):150-5. doi: 10.1159/000125566.
In the aged rat, the activity of the hypothalamo-pituitary-adrenocortical (HPA) axis was found to be increased. In fact, the plasma corticosterone concentrations in the aged (25 months) Sprague-Dawley rat were higher than in the young (3 months) Sprague-Dawley rat. To determine which component of the HPA axis principally contributes to this hyperactivity, an in vitro approach was applied. Neither the adrenal nor the pituitary revealed any age-induced modification in their basal or hormone-stimulated in vitro activity. Moreover, the ability of corticosterone to inhibit the in vitro stimulated pituitary adrenocorticotropic hormone release was preserved in aged rats. On the contrary, the in vitro hypothalamic activity was altered in aged rats. The basal and stimulated release of bioactive corticotropin-releasing factor were increased in aged rats. The results obtained in this study indicate that the hypercorticosteronemia of the aged Sprague-Dawley rat is associated with hypothalamic hyperactivity and with normal in vitro activity and reactivity of the adrenal and pituitary.
在老年大鼠中，发现下丘脑 - 垂体 - 肾上腺皮质（HPA）轴的活性增加。事实上，老年（25个月）斯普拉格 - 道利大鼠的血浆皮质酮浓度高于年轻（3个月）斯普拉格 - 道利大鼠。为了确定HPA轴的哪个组成部分主要导致这种活性亢进，采用了体外研究方法。肾上腺和垂体在其基础或激素刺激的体外活性方面均未显示出任何年龄诱导的变化。此外，皮质酮抑制体外刺激的垂体促肾上腺皮质激素释放的能力在老年大鼠中得以保留。相反，老年大鼠的体外下丘脑活性发生了改变。老年大鼠中生物活性促肾上腺皮质激素释放因子的基础释放和刺激释放均增加。本研究获得的结果表明，老年斯普拉格 - 道利大鼠的高皮质酮血症与下丘脑活性亢进以及肾上腺和垂体正常的体外活性和反应性有关。
