Department of Integrative Biology, University of Guelph, Guelph, Canada.
Zebrafish. 2010 Dec;7(4):349-58. doi: 10.1089/zeb.2010.0662. Epub 2010 Nov 22.
The dynamic relationships between the changes in cortisol synthesis during and after a stressor and the expression pattern of the key genes that regulate the different levels of the hypothalamic-pituitary-interrenal (HPI) stress axis are poorly understood. This study established a novel vortex stressor and characterized its impact at all levels of the HPI axis in adult zebrafish. Exposure to a moderate vortex speed for 60 min was associated with a marked 18-fold increase in whole-body cortisol after 10 min followed by a gradual return to basal values 30 min poststress. The changes in whole-body cortisol were paralleled by increases in the expression of preoptic area corticotropin-releasing factor, pituitary prohormone convertase 1, and interrenal melanocortin 2 receptor, steroid acute regulatory protein, 11β-hydroxylase and 11β-hydroxysteroid dehydrogenase 2. The response to the vortex stressor also included delayed increases in preoptic area urotensin I and pituitary pro-opiomelanocortin mRNA levels but no change in the expression of other putative HPI axis regulators. Notably, the expression of several genes was depressed below control values 30 min poststress. These findings suggest that multiple genes at all levels of the HPI axis play an active role in the stimulation and termination of the cortisol stress response in zebrafish.
在应激期间和之后，皮质醇合成的变化与调节下丘脑-垂体-肾上腺（HPI）轴不同水平的关键基因表达模式之间的动态关系尚未得到很好的理解。本研究建立了一种新型涡流应激器，并描述了其在成年斑马鱼 HPI 轴各个水平的影响。暴露于中等涡流速度 60 分钟后，全身皮质醇在应激后 10 分钟增加了 18 倍，随后逐渐恢复到基础值 30 分钟。全身皮质醇的变化与前脑促肾上腺皮质释放因子、垂体促激素原转换酶 1 和肾上腺黑素细胞刺激素 2 受体、类固醇急性调节蛋白、11β-羟化酶和 11β-羟固醇脱氢酶 2 的表达增加相平行。对涡流应激器的反应还包括前脑促尿钠排泄肽 I 和垂体前促黑激素原 mRNA 水平的延迟增加，但其他假定的 HPI 轴调节剂的表达没有变化。值得注意的是，应激后 30 分钟，一些基因的表达低于对照值。这些发现表明，HPI 轴各个水平的多个基因在刺激和终止斑马鱼皮质醇应激反应中发挥积极作用。
