Regulation of IGFBP-2 gene expression in rat insulin producing cell line INS-1

AIM: To study the effects of glucose, insulin and growth hormone (GH) on expression of IGFBP-2 (insulin-like growth factor binding protein 2) mRNA in INS-1 cell line and to analyze the mechanism of IGFBP-2 regulation. METHODS: Northern blot analysis was performed for the expression of IGFBP-2 mRNA and enzyme-linked immunoadsorbent assay for the determination of insulin release in this cell-line. RESLUTS: Northern blot analysis showed that different glucose concentration could make a discordant effect on IGFBP-2 gene expression. The secretion of insulin increased and the expression of IGFBP-2 mRNA was suppressed when cells were kept at high glucose concentration. On the contrary, IGFBP-2 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 IGFBP-2 and at the same time the secretion of insulin increased. The expression of IGFBP-2 mRNA was inhibited by exogenous insulin at a low glucose concentration condition. CONCLUSION: The effects of glucose and GH on the expression of IGFBP-2 mRNA are inhibited by insulin.