Abstract: ObjectiveTo observe the expression of insulin receptor substrate2 （IRS2）on intrauterine growth retardation（IUGR），and to investigate molecular mechanisms for insulin resistance in IUGR rats. MethodsAn IUGR animal model was established by protein malnutrition during pregnancy.Study the expression of IRS2 by immunohistochemistry at newborn，at 3 weeks and 8 weeks respectively on control group fed with common diet and IUGR lowprotein diet group. ResultsThe level of protein of IRS2 at newborn，3 weeks and 8 weeks of IUGR was significantly lower than that of control group respectively. ConclusionIUGR can induce the obstacle of signal transduction and effecter molecule by impacting on IRS2，which might be one of the molecular mechanisms of IUGR with insulin resistance at adult.

Key words: Fetal growth retardation；Fetus/Embryology；Receptors, insulin；Rats；Animals, laboratory