Martin C I, Johnston I A
Gatty Marine Laboratory, School of Biology, University of St Andrews, St Andrews, Scotland KY16 8LB, UK.
J Exp Biol. 2005 Jun;208(Pt 11):2083-90. doi: 10.1242/jeb.01605.
Rainbow trout Oncorhynchus mykiss Walbaum were exercised at 0.8 and 1.6 body lengths s(-1) for 18 h a day over a 30 day period. Exercise resulted in a 24-30% increase in the average cross-sectional area of fast muscle fibres relative to tank-rested controls. The concentrations of growth factors and transcription factors hypothesised to play a role in regulating exercise-induced muscle fibre hypertrophy were measured. Exercise training resulted in a minor increase in calcineurin localisation in the nucleus. However, nuclear factor of T-cells 2 (NFAT2) nuclear localisation did not follow a pattern that was consistent with NFAT2-mediated transcriptional activity and changes in calcineurin signaling. The active peptide of myostatin, a negative regulator of muscle growth in mammals, was downregulated in exercise groups relative to tank-rested controls, but only by 6-7%. It was concluded that myostatin and calcineurin signaling do not play a major role in regulating exercise-induced muscle hypertrophy in trout.
虹鳟鱼（Oncorhynchus mykiss Walbaum）在30天的时间里，每天以0.8和1.6体长每秒的速度运动18小时。与饲养在水族箱中静止不动的对照组相比，运动使快肌纤维的平均横截面积增加了24%-30%。研究人员测量了假设在调节运动诱导的肌纤维肥大中起作用的生长因子和转录因子的浓度。运动训练导致钙调神经磷酸酶在细胞核中的定位略有增加。然而，T细胞核因子2（NFAT2）的核定位模式与NFAT2介导的转录活性和钙调神经磷酸酶信号变化不一致。在哺乳动物中，肌肉生长抑制素是肌肉生长的负调节因子，其活性肽在运动组中相对于饲养在水族箱中静止不动的对照组有所下调，但仅下调了6%-7%。研究得出结论，肌肉生长抑制素和钙调神经磷酸酶信号在调节虹鳟鱼运动诱导的肌肉肥大中不起主要作用。
