Exercise training and calorie restriction increase SREBP-1 expression and intramuscular triglyceride in skeletal muscle.
Exercise training and calorie restriction increase SREBP-1 expression and intramuscular triglyceride in skeletal muscle.
复制标题
运动训练和热量限制会增加骨骼肌中 SREBP-1 的表达和肌内甘油三酯。
DOI：
10.1152/ajpendo.00543.2005
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Draznin,Boris
中科院分区：
文献类型：
--
作者：
Nadeau,KristenJ;Ehlers,LindsayB;Aguirre,LinaE;Moore,RussellL;Jew,KorinneN;Ortmeyer,HeidiK;Hansen,BarbaraC;Reusch,JaneEB;Draznin,Boris
Intramuscular triglyceride (IMTG) deposition in skeletal muscle is associated with obesity and type 2 diabetes (T2DM) and is thought to be related to insulin resistance (IR). Curiously, despite enhanced skeletal muscle insulin sensitivity, highly trained athletes and calorie-restricted (CR) monkeys also have increased IMTG. Sterol regulatory element-binding proteins (SREBPs) are transcription factors that regulate the biosynthesis of cholesterol and fatty acids. SREBP-1 is increased by insulin in skeletal muscle in vitro and in skeletal muscle of IR subjects, but SREBP-1 expression has not been examined in exercise training or calorie restriction. We examined the relationship between IMTG and SREBP-1 expression in animal models of exercise and calorie restriction. Gastrocnemius and soleus muscle biopsies were obtained from 38 Sprague-Dawley rats (18 control and 20 exercise trained). Triglyceride content was higher in the gastrocnemius and soleus muscles of the trained rats. SREBP-1c mRNA, SREBP-1 precursor and mature proteins, and fatty acid synthase (FAS) protein were increased with exercise training. Monkeys (Macaca mulatta) were CR for a mean of 10.4 years, preventing weight gain and IR. Vastus lateralis muscle was obtained from 12 monkeys (6 CR and 6 controls). SREBP-1 precursor and mature proteins and FAS protein were higher in the CR monkeys. In addition, phosphorylation of ERK1/ERK2 was increased in skeletal muscle of CR animals. In summary, SREBP-1 protein and SREBP-1c mRNA are increased in interventions that increase IMTG despite enhanced insulin sensitivity. CR and exercise-induced augmentation of SREBP-1 expression may be responsible for the increased IMTG seen in skeletal muscle of highly conditioned athletes.
