Palmer W K, Oscai L B, Bechtel P J, Fisher G A
Department of Physical Education, University of Illinois, Chicago 60680.
Can J Physiol Pharmacol. 1990 Jun;68(6):689-93. doi: 10.1139/y90-104.
Triacylglycerol (TG) lipase activity, with an alkaline pH optimum, has been identified in the cellular fraction of L8 myotube cultures. This TG lipase activity was stimulated by serum and inhibited by NaCl and protamine sulfate. These characteristics have been classically described for lipoprotein lipase. It was possible to increase the activity of this TG lipase three- to five-fold by incubating the cells with dibutyryl cAMP. Maximal enzyme activity was observed 16 h following the addition of 10-100 microM dibutyryl cAMP to the cultured cells. Enzyme activity returned to control levels 24 h after removal of the nucleotide from the culture medium. Serum-sensitive alkaline TG lipase activity was also identified in five other myotube preparations of cultured muscle cells. The highest levels of activity were found in rat skeletal muscle primary, H9, and L6 cell types. The finding that dibutyryl cAMP is an effective inducer of alkaline TG lipase activity provides us with a valuable model to investigate mechanisms regulating synthesis, compartmentalization, and transport of lipoprotein lipase in muscle.
在L8肌管培养物的细胞组分中已鉴定出具有碱性最适pH值的三酰甘油（TG）脂肪酶活性。这种TG脂肪酶活性受到血清刺激，并被氯化钠和硫酸鱼精蛋白抑制。这些特性是脂蛋白脂肪酶的经典描述。通过用二丁酰环磷腺苷（dibutyryl cAMP）孵育细胞，有可能使这种TG脂肪酶的活性提高三到五倍。在向培养细胞中添加10 - 100微摩尔二丁酰环磷腺苷后16小时观察到最大酶活性。从培养基中去除核苷酸24小时后，酶活性恢复到对照水平。在培养的肌肉细胞的其他五种肌管制剂中也鉴定出了血清敏感性碱性TG脂肪酶活性。在大鼠骨骼肌原代细胞、H9细胞和L6细胞类型中发现了最高水平的活性。二丁酰环磷腺苷是碱性TG脂肪酶活性的有效诱导剂这一发现，为我们提供了一个有价值的模型，用于研究调节肌肉中脂蛋白脂肪酶的合成、区室化和转运的机制。
