Brett L P, Levine R, Levine S
Neurobiol Aging. 1986 May-Jun;7(3):153-9. doi: 10.1016/0197-4580(86)90036-9.
Bidirectional responsiveness of the pituitary-adrenal system was examined in young adult (3-5 months) and old (24-26 months) male and female rats. In Experiment 1, an approach-avoidance conflict was created by exposing food- and water-deprived subjects to a flavored solution which had previously been paired with lithium chloride-induced illness in a conditioned taste aversion paradigm. Young and old males and young females elevated plasma corticosterone in response to deprivation; males showed a further elevation when reexposed to the solution, whereas young females did not. Old females did not exhibit a corticosterone elevation to deprivation or upon reexposure. In Experiment 2, water was restricted to a fixed period in the morning when corticosterone levels are typically low. Plasma corticosterone was measured before and after watering. Young and old males and young females reentrained their circadian corticosterone rhythm so that levels were elevated just prior to watering; consumption was followed by a drop in corticosterone. Old females failed to reentrain or to suppress corticosterone secretion upon drinking. These findings indicate that the lability of the pituitary-adrenal system is more markedly affected by senescence in females than in males.
在年轻成年（3 - 5个月）和老年（24 - 26个月）的雄性和雌性大鼠中，研究了垂体 - 肾上腺系统的双向反应性。在实验1中，通过将剥夺食物和水的实验对象暴露于一种有味道的溶液来制造一种趋近 - 回避冲突，该溶液在条件性味觉厌恶范式中先前曾与氯化锂诱导的疾病配对。年轻和老年雄性以及年轻雌性在面对剥夺时血浆皮质酮升高；雄性在再次接触该溶液时皮质酮进一步升高，而年轻雌性则没有。老年雌性在面对剥夺或再次接触时未表现出皮质酮升高。在实验2中，在早晨皮质酮水平通常较低的固定时间段限制饮水。在饮水前后测量血浆皮质酮。年轻和老年雄性以及年轻雌性重新调整了它们的昼夜皮质酮节律，使得在饮水前皮质酮水平升高；饮水后皮质酮水平下降。老年雌性在饮水时未能重新调整或抑制皮质酮分泌。这些发现表明，垂体 - 肾上腺系统的易变性在雌性中比在雄性中更明显地受到衰老的影响。
