营养快速提升造成的追赶生长是发展中国家糖尿病急速蔓延的重要原因。内脏脂肪脂质过度生成、骨骼肌脂质沉积与线粒体功能受损是促使追赶生长胰岛素抵抗形成的关键代谢改变，但机制未明。新近研究表明，支链氨基酸(BCAAs)分解代谢异常与胰岛素抵抗形成密切相关，关联强度甚至超过脂质。我们的前期研究亦揭示，追赶生长过程中BCAAs分解代谢关键酶表达水平/活性发生持续变化，从而造成BCAAs分解代谢异常活跃。故推测：经表观遗传修饰，限食期因供能不足激活的BCAAs分解代谢至恢复饮食期仍过度活跃，终诱发前述关键代谢改变。我们拟通过体内外实验，明确BCAAs分解代谢中间产物、关键酶及其表观遗传修饰在追赶生长胰岛素抵抗发生中的作用；筛查在上述过程中有重要作用的BCAAs代谢中间产物；探究限食期不同浓度BCAAs保全对追赶生长大鼠代谢的影响。研究结果将为胰岛素抵抗的发病机制提供新认识，为膳食指南的修订提供重要依据。

Catch-up growth induced by rapid improvement in nutrition level has been generally recognized as an important reason for the high prevalence of diabetes mellitus in developing countries. Excess lipogenesis in visceral adipose tissue，ectopic lipid deposition and mitochondrial dysfunction in skeletal muscle are the fundamental abnormalities in the development of insulin resistance in catch-up growth. However, the underlying mechanism still remains unclear. It is lately reported that the disturbed branched-chain amino acids metabolism and accumulation of toxic intermediates have a large bearing upon the above abnormalities. Our previous studies revealed that the expression /activities of some key enzymes in branched-chain amino acids metabolism continued to change from caloric restriction period to refeeding period in the visceral adipose tissue and skeletal muscle of catch-up growth rats. Accordingly, we hypothesize that catch-up growth might regulate the expression/activities of key enzymes in branched-chain amino acids metabolism through epigenetic modification, thereby disturbing branched-chain amino acids metabolism, reinforcing the accumulation of toxic intermediates and causing insulin resistance. The present study intends to determine the role of branched-chain amino acids metabolism, certain toxic intermediates and the epigenetic modification for genes coding the key enzymes in branched-chain amino acids metabolism in the development of insulin resistance in catch-up growth both in vivo and in vitro; to screen vital intermediates which also play an important role in the process through liquid chromatography-massspectrometry; to explore the impact of different levels of branched-chain amino acids intake on the development of insulin resistance in catch-up growth. The results are expected to provide new ideas for the mechanism, prevention and treatment of insulin resistance related diseases, and to produce solid evidence which the revision of dietary guidelines could be based on.