Davis Kenneth B, Peterson Brian C
USDA/ARS Harry K. Dupree Stuttgart National Aquaculture Research Center, P.O. Box 1050, Stuttgart, AR 72160, USA.
Gen Comp Endocrinol. 2006 Dec;149(3):219-25. doi: 10.1016/j.ygcen.2006.05.009. Epub 2006 Jul 18.
The mechanisms through which stress and cortisol regulate insulin like growth factor-I (IGF-I) and insulin like growth factor binding proteins (IGFBPs) were studied in sunshine bass, by measuring plasma IGF-I and IGFBPs in fish maintained at 5, 10, 15, 20, 25, or 30 degrees C, fish subjected to an acute 15 min confinement stress at 25 and 30 degrees C, and fish fed 100 mg cortisol/kg feed. Plasma IGF-I concentrations were higher at 25 and 30 degrees C than at 20 degrees C and below. A 15 min confinement stress resulted in a decrease in IGF-I 2h post-confinement. Plasma concentrations of IGFBP with molecular weights of 24, 28, and 33 kDa were similar for fish acclimated to different temperatures, except for 5 degrees C where a 33-kDa IGFBP was significantly reduced. After a 15 min low-water stress at 25 degrees C, a 33-kDa IGFBP was reduced and IGFBPs with molecular weights of 24 and 28 kDa were increased at 2 and 6h, respectively. A 15 min low-water stress at 30 degrees C, resulted in no change in levels of a 33-kDa IGFBP over the 6-h recovery period. However, levels of a 24- and 28-kDa IGFBP were significantly increased at 2 and 6h, respectively. A single feeding with 100 mg cortisol/kg feed increased plasma cortisol but did affect plasma concentrations of IGF-I or any of the three IGFBPs. Acute stress appears to result in a decrease in IGF-I, but the mechanism of the decrease does not appear to be caused by cortisol released during the stress.
通过测量处于5、10、15、20、25或30摄氏度环境中的阳光鲈血浆中胰岛素样生长因子-I（IGF-I）和胰岛素样生长因子结合蛋白（IGFBPs），对遭受急性15分钟限制应激的25和30摄氏度的鱼，以及喂食100毫克皮质醇/千克饲料的鱼进行研究，以探究应激和皮质醇调节胰岛素样生长因子-I（IGF-I）和胰岛素样生长因子结合蛋白（IGFBPs）的机制。25和30摄氏度时的血浆IGF-I浓度高于20摄氏度及以下时的浓度。15分钟的限制应激导致应激后2小时IGF-I降低。适应不同温度的鱼，其分子量为24、28和33千道尔顿的IGFBP血浆浓度相似，但在5摄氏度时，33千道尔顿的IGFBP显著降低。在25摄氏度下进行15分钟的低水位应激后，33千道尔顿的IGFBP在2小时和6小时分别降低和升高，分子量为24和28千道尔顿的IGFBP在2小时和6小时分别升高。在30摄氏度下进行15分钟的低水位应激，在6小时的恢复期内，33千道尔顿的IGFBP水平没有变化。然而，24和28千道尔顿的IGFBP水平在2小时和6小时分别显著升高。单次喂食100毫克皮质醇/千克饲料会增加血浆皮质醇，但不影响血浆IGF-I浓度或三种IGFBPs中的任何一种。急性应激似乎导致IGF-I降低，但这种降低的机制似乎不是由应激期间释放的皮质醇引起的。
