Regulation of IGFBPª²2 gene expression in rat insulin producing cell line INSª²1

    ZHANG Chunª²Ju, YUAN Li, ZHOU Jinª²Yong, DE Wei

    Department of Biochemistry and Molecular Biology£¬Nanjing Medical University, Nanjing 210029, China

    ¡¾Abstract¡¿ AIM: To study the effects of glucose, insulin and growth hormone (GH) on expression of IGFBPª²2 (insulinª²like growth factor binding protein 2) mRNA in INSª²1 cell line and to analyze the mechanism of IGFBPª²2 regulation. METHODS: Northern blot analysis was performed for the expression of IGFBPª²2 mRNA and enzymeª²linked immunoadsorbent assay for the determination of insulin release in this cellª²line. RESLUTS: Northern blot analysis showed that different glucose concentration could make a discordant effect on IGFBPª²2 gene expression. The secretion of insulin increased and the expression of IGFBPª²2 mRNA was suppressed when cells were kept at high glucose concentration. On the contrary, IGFBPª²2 mRNA could be well detected in cells that were kept at low glucose while the insulin secreted normally. After 16h incubation, exogenous GH inhibited the expression of IGFBPª²2 and at the same time the secretion of insulin increased. The expression of IGFBPª²2 mRNA was inhibited by exogenous insulin at a low glucose concentration condition. CONCLUSION: The effects of glucose and GH on the expression of IGFBPª²2 mRNA are inhibited by insulin. ......