Maternal exposure to stressors during lactation has previously been demonstrated to impact various aspects of milk synthesis and to have long-term physiological effects on offspring. Much of the current literature investigating the effects of stress during lactation has used acute stressors, and the studies investigating the effects of chronic stressors largely focus on neurological changes. Further, temporal variation in glucocorticoids across lactation in response to stressors has rarely been assessed. The present work uses a novel male intruder paradigm to model the effects of chronic stress on maternal fecal corticosterone metabolites (FCMs) in Sprague-Dawley rats across lactation. FCM levels were elevated in chronically-stressed mothers relative to the control group. Further, FCMs in the stress group were time-dependent either due to repeated exposure to the stressor or lactation stage. Together, this work demonstrates the efficacy of this established paradigm in increasing circulating glucocorticoids in lactating rats. These results highlight the need for repeated temporal sampling, as glucocorticoid levels in response to a chronic stressor may change across lactation.

先前已证明母体在哺乳期间暴露于压力源会影响乳汁合成的各个方面并对后代产生长期的生理影响。目前研究哺乳期压力影响的大部分文献都使用了急性压力源，而研究慢性压力源影响的研究主要集中在神经系统变化上。此外，很少评估糖皮质激素在整个哺乳期响应压力源的时间变化。目前的工作使用一种新的男性入侵者范式来模拟慢性压力对 Sprague-Dawley 大鼠哺乳期母体粪便皮质酮代谢物 (FCM) 的影响。相对于对照组，长期压力大的母亲的 FCM 水平升高。进一步，由于反复暴露于压力源或哺乳期，压力组中的 FCM 具有时间依赖性。总之，这项工作证明了这种既定范例在增加哺乳大鼠循环糖皮质激素方面的功效。这些结果强调了重复时间采样的必要性，因为响应慢性压力源的糖皮质激素水平可能会在整个哺乳期发生变化。