Department of Biological Sciences, The University of Memphis, 3774 Walker Ave. Memphis, TN 38152, USA.
Horm Behav. 2011 Apr;59(4):497-502. doi: 10.1016/j.yhbeh.2011.01.010. Epub 2011 Feb 2.
Recent studies have posited that the pattern of glucocorticoid secretion within an individual represents a stable, fixed physiological trait. To test this hypothesis, we assessed the repeatability of baseline and stress-induced corticosterone (CORT) secretion across developmental stages and years in Florida scrub-jays. We sampled individuals from multiple cohorts repeatedly from the age of 11 days post-hatch up to 4 years of age. We found a significant degree of repeatability within individuals in stress-induced corticosterone levels, i.e., the amount of hormone secreted during a standardized stress protocol (corrected integrated corticosterone). However, baseline corticosterone levels were not statistically repeatable, although there was some indication that nestling levels predicted levels at 1 year of age. The results of this study indicate that stress-induced CORT levels are consistent within individual scrub-jays, and the degree to which a young jay mounts an acute stress response appears to be somewhat "set" by the age of nutritional independence. Thus stress-induced corticosterone secretion appears to be a stable, repeatable trait within individuals and as such may be subject to natural selection.
最近的研究提出，个体内部糖皮质激素分泌的模式代表了一种稳定的、固定的生理特征。为了验证这一假设，我们评估了佛罗里达州灌丛鸦在发育阶段和多年内基础和应激诱导的皮质酮（CORT）分泌的可重复性。我们从多个队列中取样，从孵化后 11 天开始，一直到 4 岁。我们发现个体在应激诱导的皮质酮水平上具有显著的可重复性，即在标准化应激方案期间分泌的激素量（校正后的整合皮质酮）。然而，基础皮质酮水平在统计学上不可重复，尽管有一些迹象表明巢幼期水平可以预测 1 岁时的水平。这项研究的结果表明，应激诱导的 CORT 水平在个体灌丛鸦中是一致的，幼鸦对急性应激反应的程度似乎在营养独立的年龄时就有所“设定”。因此，应激诱导的皮质酮分泌似乎是个体内部稳定的、可重复的特征，因此可能受到自然选择的影响。
