The expressions of insulin receptor substrate in adipocytes during catch-up growth in neonatal rats with intrauterine growth retardation

  • ZHENG Ruidan ,
  • GAO Jinzhi ,
  • YING Yanqin ,
  • NING Qin ,
  •  WANG Chengbin ,
  • LIAO Lihong ,
  • YE Juan ,
  • LUO Xiaoping
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  • 1.Department of Pediatrics, Tongji Hospital affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China; 2. Department of Pediatrics, Xiangyang Central Hospital, Xiangyang 441021, Hubei, China

Received date: 2014-12-15

  Online published: 2014-12-15

Abstract

Objective To investigate the expressions of insulin receptor substrate-1 (IRS-1) and insulin receptor substrate-2 (IRS-2) in adipocytes during catch-up growth in neonatal rats with intrauterine growth restriction (IUGR) and their correlations with the insulin resistance. Methods Sprague-Dawley rats (clean grade) were randomly divided into control group and food-restricted group after fertilization. Food-restricted group were received about 30% of food amount consumed in control group every day through the whole pregnant period to establish IUGR animal model, and were fed increased amount of breastmilk from postnatal day 1 to 21 to establish the period of catch-up growth in IUGR animal model (IUGR-CG). Fasting serum glucose, insulin and triglyceride were measured in blood from heart ventricles of 4-week old SD rats and insulin resistance index was calculated. Pre-adipocytes and mature adipocytes were obtained from SD rats at different age (1-week, 3-week, 5-week and 7-week old) and the former were induced to differentiate toward mature adipocytes. The levels of IRS-1, IRS-2 in the two kinds of mature adipocytes were detected by Real-Time PCR and Western blot. Results The expression levels of IRS-1, IRS-2 mRNA in mature adipocytes of IUGR-CG rats were significantly lower than those of IUGR rats at 5-weeks and 7-weeks old (P<0.05) while the expression levels of IRS-1, IRS-2 mRNA in differentiated adipocytes of IUGR-CG rats were significantly lower than those of IUGR rats at 5-weeks old (P<0.05). The expression levels of IRS-1, IRS-2 protein in two kinds of adipocytes (mature and differentiated adipocytes) of IUGR-CG rats were significantly lower than those of IUGR rats from postpartum week 1 through 7 (P<0.05). Conclusions IRS-1 and IRS-2 expression levels are downregulated in adipocytes during catch-up growth of IUGR rats, which may be closely related with insulin resistance.

Cite this article

ZHENG Ruidan , GAO Jinzhi , YING Yanqin , NING Qin ,  WANG Chengbin , LIAO Lihong , YE Juan , LUO Xiaoping . The expressions of insulin receptor substrate in adipocytes during catch-up growth in neonatal rats with intrauterine growth retardation[J]. Journal of Clinical Pediatrics, 2014 , 32(12) : 1162 . DOI: 10.3969 j.issn.1000-3606.2014.12.017

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