Vágási Csongor I, Pătraș Laura, Pap Péter L, Vincze Orsolya, Mureșan Cosmin, Németh József, Lendvai Ádám Z
Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Cluj Napoca, Romania.
Behavioural Ecology Research Group, Department of Evolutionary Zoology, University of Debrecen, Debrecen, Hungary.
PLoS One. 2018 Feb 12;13(2):e0192701. doi: 10.1371/journal.pone.0192701. eCollection 2018.
Glucocorticoid (GC) hormones are significant regulators of homeostasis. The physiological effects of GCs critically depend on the time of exposure (short vs. long) as well as on their circulating levels (baseline vs. stress-induced). Previous experiments, in which chronic and high elevation of GC levels was induced, indicate that GCs impair both the activity of the immune system and the oxidative balance. Nonetheless, our knowledge on how mildly elevated GC levels, a situation much more common in nature, might influence homeostasis is limited. Therefore, we studied whether an increase in GC level within the baseline range suppresses or enhances condition (body mass, hematocrit and coccidian infestation) and physiological state (humoral innate immune system activity and oxidative balance). We implanted captive house sparrows Passer domesticus with either 60 days release corticosterone (CORT) or control pellets. CORT-treated birds had elevated baseline CORT levels one week after the implantation, but following this CORT returned to its pre-treatment level and the experimental groups had similar CORT levels one and two months following the implantation. The mass of tail feathers grown during the initial phase of treatment was smaller in treated than in control birds. CORT implantation had a transient negative effect on body mass and hematocrit, but both of these traits resumed the pre-treatment values by one month post-treatment. CORT treatment lowered oxidative damage to lipids (malondialdehyde) and enhanced constitutive innate immunity at one week and one month post-implantation. Our findings suggest that a relatively short-term (i.e. few days) elevation of baseline CORT might have a positive and stimulatory effect on animal physiology.
糖皮质激素（GC）是体内稳态的重要调节因子。GC的生理效应严重依赖于暴露时间（短期与长期）及其循环水平（基线水平与应激诱导水平）。此前诱导GC水平长期大幅升高的实验表明，GC会损害免疫系统的活性和氧化平衡。然而，对于自然环境中更为常见的GC水平轻度升高如何影响体内稳态，我们的了解还很有限。因此，我们研究了基线范围内GC水平的升高是会抑制还是增强动物的身体状况（体重、血细胞比容和球虫感染情况）和生理状态（体液固有免疫系统活性和氧化平衡）。我们给圈养的家麻雀（Passer domesticus）植入了可在60天内释放皮质酮（CORT）的药丸或对照药丸。植入后一周，接受CORT处理的鸟类基线CORT水平升高，但此后CORT恢复到处理前水平，且在植入后1个月和2个月时，实验组的CORT水平相似。在处理初期生长的尾羽质量，处理组的比对照组的小。CORT植入对体重和血细胞比容有短暂的负面影响，但在处理后1个月，这两个指标都恢复到了处理前的值。CORT处理降低了脂质的氧化损伤（丙二醛含量），并在植入后1周和1个月时增强了组成型固有免疫。我们的研究结果表明，基线CORT相对短期（即几天）的升高可能对动物生理产生积极的刺激作用。
