Our understanding of the importance of cortisol in the development of fishes largely stems from teleosts and in particular the zebrafish, Danio rerio. However, studies examining the ontogeny of the cortisol endocrine axis in acipenseriformes (sturgeon and paddlefish) have demonstrated similar general patterns during early development. Beginning with maternal deposition of cortisol in the egg, followed by development of de novo synthesis, a hypo-responsive period, and finally the ability of the fish to appropriately increase whole-body levels of cortisol in response to a stressor. In the present study, we demonstrate a similar pattern of ontogeny in the cortisol response in lake sturgeon over two-year classes. Whole-body levels of cortisol were examined over two cohorts and found to be different in both concentration and timing of endogenous production. The 2016 cohort were found to have relatively high levels of cortisol and developed to first feeding approximately six days faster than the 2017 cohort with lower levels of cortisol. In the 2017 cohort, mRNA expression of steroidogenic acute regulatory protein (StAR) and glucocorticoid receptor 1 (GR1) increased just prior to the increase in cortisol and associated onset of exogenous feeding. Treatment in metyrapone, an inhibitor of 11β-hydroxylase, significantly inhibited cortisol production and resulted in the inability of the fish to appropriately transition to exogenous feeding. Data suggest a potential key role for cortisol in lake sturgeon as they transition between diets during early life history.

我们对皮质醇在鱼类发育中的重要性的理解主要源于硬骨鱼，尤其是斑马鱼Danio rerio。但是，研究对头足纲动物（st鱼和dle鱼）的皮质醇内分泌轴的个体发育的研究表明，在早期发育过程中存在相似的一般模式。从母体中的皮质醇在卵中沉积开始，然后从头发展合成，反应不足的时期，最后是鱼类对应激源的反应，能够适当提高全身皮质醇水平的能力。在本研究中，我们证明了在两年课程中st鱼的皮质醇反应中个体发育的相似模式。在两个队列中检查了全身皮质醇水平，发现内源性生产的浓度和时间不同。发现2016年队列中的皮质醇水平相对较高，并且比2017年队列中皮质醇水平较低的人群首次进食的速度快约六天。在2017年队列中，类固醇生成的急性调节蛋白（StAR）和糖皮质激素受体1（GR1）在皮质醇升高和相关的外源性进食开始之前就升高了。甲吡酮（一种11β-羟化酶的抑制剂）的处理显着抑制了皮质醇的产生，并导致鱼类无法适当过渡到外来摄食。数据表明，皮质醇在lake鱼中的潜在关键作用是它们在生命的早期阶段之间在饮食之间的过渡。