Understanding Context Dependence in Glucocorticoid–Fitness Relationships: The Role of the Nature of the Challenge, the Intensity and Frequency of Stressors, and Life History
Understanding Context Dependence in Glucocorticoid–Fitness Relationships: The Role of the Nature of the Challenge, the Intensity and Frequency of Stressors, and Life History
复制标题
了解糖皮质激素与健身关系中的情境依赖性：挑战性质、压力源的强度和频率以及生活史的作用
DOI：
10.1093/icb/icy046
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发表时间：
2018
影响因子：
2.6
通讯作者：
Vitousek, Maren N
中科院分区：
文献类型：
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作者：
Schoenle, Laura A;Zimmer, Cedric;Vitousek, Maren N
众所周知，循环中的糖皮质激素(GC)与健康之间的关系在强度和方向上存在差异。当研究表明这种差异或GC-适应度关系的方向出乎意料时，结果往往被归因于上下文依赖。然而，背景的描述可能是模糊的(例如，“环境背景”)，很少有研究明确地测试最佳的下丘脑-垂体-肾上腺(HPA)轴对应激源的反应如何在特定的背景下变化。尽管现有的假设为理解GC-适应性关系奠定了坚实的基础，但许多假设并没有明确预测这种关系将如何、何时以及为什么会发生变化。在这里，我们讨论了三个广泛的因素，我们期望塑造HPA轴活动和健康指标之间的关系：(1)HPA轴介导的反应是否与挑战匹配，(2)挑战的强度和频率，以及(3)生活史。我们还对这些因素如何影响GC-适应度关系进行了预测，并讨论了测试这些预测的方法。观察性研究、环境实验操作和大规模跨物种比较将对理解观察到的GC-适应度关系的变化至关重要。
It has been well-established that there is variation in the strength and direction of the relationship between circulating glucocorticoids (GCs) and fitness. When studies demonstrate such variation or the direction of the GC–fitness relationship is unexpected, the results are often attributed to context-dependency. However, descriptors of context can be vague (e.g., “environmental context”) and few studies explicitly test how the optimal hypothalamic–pituitary–adrenal (HPA) axis response to stressors varies across specific contexts. Although existing hypotheses create a strong foundation for understanding GC–fitness relationships, many do not provide explicit predictions of how, when, and why the relationships will change. Here, we discuss three broad factors which we expect to shape the relationships between HPA axis activity and fitness metrics: (1) whether the HPA axis-mediated response matches the challenge, (2) the intensity and frequency of challenges, and (3) life history. We also make predictions for how these factors might affect GC–fitness relationships and discuss ways to test these predictions. Observational studies, experimental manipulations of context, and large-scale cross-species comparisons will be critical to understanding the observed variation in GC–fitness relationships.