Balage M, Grizard J, Sornet C, Simon J, Dardevet D, Manin M
Laboratoire d'Etude du Métabolisme Azoté, Centre de Clermont-Theix, Ceyrat, France.
Metabolism. 1990 Apr;39(4):366-73. doi: 10.1016/0026-0495(90)90250-g.
Insulin binding and insulin receptor kinase activity were measured in solubilized and partially purified receptor preparations from liver and skeletal muscles of rats that were either fed a standard diet or subjected to a 72-hour fasting period. Insulin binding capacity was increased in both tissues from fasted rats as determined by Scatchard analysis. The affinity of the receptors was not modified by fasting. Affinity labeling of the alpha-subunit of insulin receptors also suggested an increase in the number of insulin receptors in both tissues. The ability of insulin to stimulate the autophosphorylation of the beta-subunit as well as the phosphorylation of the artificial substrate Glu80-Tyr20 was significantly impaired in liver from fasted rats and by contrast unchanged in skeletal muscles. These findings indicate that in rats, fasting produces changes in insulin receptor kinase activity in liver but not in muscle. The physiological significance of this tissue-specific regulation of receptor kinase activity in relation to insulin action during fasting remains to be established.
在喂食标准饮食或禁食72小时的大鼠的肝脏和骨骼肌中，对溶解并部分纯化的受体制剂进行胰岛素结合和胰岛素受体激酶活性测定。通过Scatchard分析确定，禁食大鼠的两种组织中的胰岛素结合能力均增加。禁食并未改变受体的亲和力。胰岛素受体α亚基的亲和标记也表明两种组织中胰岛素受体数量增加。在禁食大鼠的肝脏中，胰岛素刺激β亚基自身磷酸化以及人工底物Glu80-Tyr20磷酸化的能力显著受损，相比之下，在骨骼肌中则未改变。这些发现表明，在大鼠中，禁食会使肝脏中的胰岛素受体激酶活性发生变化，但肌肉中则不会。这种受体激酶活性的组织特异性调节在禁食期间与胰岛素作用相关的生理意义仍有待确定。
