USDA/ARS/Great Lakes WATER Institute, Milwaukee, WI 53204, USA.
Domest Anim Endocrinol. 2011 Apr;40(3):129-38. doi: 10.1016/j.domaniend.2010.09.007. Epub 2010 Oct 23.
The effects of acute stressor exposure on proximal (growth hormone [GH]) and distal (insulin-like growth factor-I [IFG-I] and insulin-like growth factor-binding proteins [IFGBPs]) components of the somatotropic axis are poorly understood in finfish. Rainbow trout (Oncorhynchus mykiss) were exposed to a 5-min handling disturbance to mimic an acute stressor episode, and levels of plasma GH, IGF-I, and IGFBPs at 0, 1, 4, and 24 h post-stressor exposure were measured. An unstressed group was also sampled at the same clock times (09:00, 10:00, 13:00, and 08:00 [the following day]) as acute stress sampling to determine temporal changes in the above somatotropic axis components. The acute stressor transiently elevated plasma cortisol and glucose levels at 1 and 4 h post-stressor exposure, whereas no changes were seen in the unstressed group. Plasma GH levels were not affected by handling stress or sampling time in the unstressed animals. Plasma IGF-I levels were significantly depressed at 1 and 4 h post-stressor exposure, but no discernible temporal pattern was seen in the unstressed animals. Using a western ligand blotting technique, we detected plasma IGFBPs of 21, 32, 42, and 50 kDa in size. The plasma levels of the lower-molecular-weight IGFBPs (21 and 32 kDa) were unaffected by handling stressor, nor were there any discernible temporal patterns in the unstressed animals. By contrast, the higher-molecular-weight IGFBPs (42 and 50 kDa) were affected by stress or time of sampling. Levels of the 42-kDa IGFBP levels significantly decreased over the sampling period in unstressed control animals, but this temporal drop was eliminated in stressed animals. Levels of the 50-kDa IGFBPs also decreased significantly over the sampling time in unstressed trout, whereas handling disturbance transiently increased levels of this IGFBP at 1 h but not at 4 and 24 h post-stressor exposure compared with the control group. Overall, our results suggest that acute stress adaptation involves modulation of plasma IGF-1 and high-molecular-mass IGFBP levels (42 and 50 kDa) in rainbow trout.
急性应激源暴露对鱼类生长激素（GH）和胰岛素样生长因子-I（IGF-I）和胰岛素样生长因子结合蛋白（IGFBPs）等生长轴近端和远端成分的影响知之甚少。虹鳟鱼（Oncorhynchus mykiss）被暴露于 5 分钟的处理干扰中以模拟急性应激源发作，并且在应激源暴露后 0、1、4 和 24 小时测量血浆 GH、IGF-I 和 IGFBPs 的水平。还在相同的时钟时间（09:00、10:00、13:00 和 08:00 [第二天]）对未受应激的组进行采样，以确定上述生长轴成分的时间变化。急性应激源在应激后 1 和 4 小时短暂地升高了血浆皮质醇和葡萄糖水平，而未受应激的组则没有变化。在未受应激的动物中，处理应激或采样时间均不影响血浆 GH 水平。在应激后 1 和 4 小时，血浆 IGF-I 水平显著降低，但在未受应激的动物中没有发现明显的时间模式。使用 Western 配体印迹技术，我们检测到大小为 21、32、42 和 50 kDa 的血浆 IGFBPs。低分子量 IGFBPs（21 和 32 kDa）的血浆水平不受处理应激源的影响，未受应激的动物也没有明显的时间模式。相比之下，高分子量 IGFBPs（42 和 50 kDa）受到应激或采样时间的影响。在未受应激的对照动物中，42-kDa IGFBP 水平在整个采样期间显著降低，但在应激动物中，这种时间下降被消除。50-kDa IGFBPs 的水平在未受应激的鳟鱼中也随着采样时间显著降低，而处理干扰在应激后 1 小时但不在 4 小时和 24 小时后短暂地增加了这种 IGFBP 的水平与对照组相比。总体而言，我们的结果表明，急性应激适应涉及虹鳟鱼血浆 IGF-1 和高分子质量 IGFBP 水平（42 和 50 kDa）的调节。
