Objective:To investigate the effect of 2,2′,4,4′-tetrabromodiphenyl ether(BDE-47) on the function and morphology of pancreatic islets and insulin sensitivity in vivo. Methods:Male mice were randomly divided into group A(normal control), group B(BDE-47-treated group,25 μg/kg), group C(BDE-47-treated group,50 μg/kg) and group D(E2-treated group,50 μg/kg). The observation time was four weeks after exposure to BDE-47. The intraperitoneal glucose tolerance test and insulin tolerance test were performed to evaluate the function of pancreatic islets and insulin sensitivity,respectively. Immunohistochemistry technique was used to measure the changes of islet morphology and quantity of mice. Results:Fasting blood glucose and glucose tolerance of the mouse were both normal on basic state. Compared with group A,the levels of fasting glucose and fasting insulin were not significantly different in group B and C after the injection of BDE-47. The peak of blood glucose level and the area under the curve(AUC) were all decreased statistically after the glucose load in group C,and the peak of insulin secretion and the AUC were both increased dramatically. No alteration of blood glucose level was found in the mice of group B and group C after insulin injection,suggesting normal insulin sensitivity. There was no statistical difference in both insulin resistance index and insulin sensitive index among three groups. The average photo-density of insulin-expression positive zone,insulin relative concentration(IRC),insulin-expression positive cell area were all increased significantly in group C. Conclusion:Low concentration of BDE-47 insulin secretion of the mouse caused elevate after glucose load,indicating that environmental endocrine disruptors play an important role in the increase of insulin content of islets and the induction of hyperinsulinemia.