Hamilton M T, Etienne J, McClure W C, Pavey B S, Holloway A K
Integrative Biology, Pharmacology, and Physiology, University of Texas Health Science Center-Houston, Houston, Texas, 77030, USA.
Am J Physiol. 1998 Dec;275(6):E1016-22. doi: 10.1152/ajpendo.1998.275.6.E1016.
The purpose of this study was to determine the influence of local contractile activity on lipoprotein lipase (LPL) regulation in skeletal muscle. Short-term voluntary run training increased LPL mRNA concentration and LPL immunoreactive mass about threefold in white skeletal muscles of the rat hindlimb (all P < 0.01). Training also increased total and heparin-releasable LPL enzyme activity in white hindlimb muscles and in postheparin plasma (P < 0.05). Training did not enhance LPL regulation in a white muscle that was not recruited during running (masseter). LPL levels were already high in red skeletal muscles of control rats, and training did not result in a further rise. In resting rats, local electrical stimulation of a motor nerve to a predominantly white muscle caused a significant rise in LPL mRNA, immunoreactive mass, and enzyme activity relative to the contralateral control muscle of the same animals (all P < 0.01). Finally, LPL expression was several times greater in a red muscle (soleus) of rats with normal postural activity than rats with immobilized hindlimbs (P < 0.01). In summary, these studies support the hypothesis that local contractile activity is required for increasing LPL expression during exercise training and for maintaining a high level of LPL expression in postural muscles.
本研究的目的是确定局部收缩活动对骨骼肌中脂蛋白脂肪酶（LPL）调节的影响。短期自愿跑步训练使大鼠后肢白色骨骼肌中的LPL mRNA浓度和LPL免疫反应性物质增加了约三倍（所有P<0.01）。训练还增加了白色后肢肌肉和肝素后血浆中的总LPL酶活性和可被肝素释放的LPL酶活性（P<0.05）。训练并未增强在跑步过程中未被募集的白色肌肉（咬肌）中的LPL调节。对照大鼠的红色骨骼肌中LPL水平已经很高，训练并未导致其进一步升高。在静息大鼠中，对主要为白色的肌肉的运动神经进行局部电刺激，相对于同一动物的对侧对照肌肉，导致LPL mRNA、免疫反应性物质和酶活性显著升高（所有P<0.01）。最后，具有正常姿势活动的大鼠的红色肌肉（比目鱼肌）中的LPL表达比后肢固定的大鼠高几倍（P<0.01）。总之，这些研究支持以下假设，即在运动训练期间增加LPL表达以及在姿势肌肉中维持高水平的LPL表达需要局部收缩活动。
