Abstract:

[Abstract] Objective To investigate the short term effect of insulin on proinsulin gene expression of HIT-T15insu? linnoma cells（pancreatic isletβ-cell）. Methods The HIT-T15cells were randomly divided into four groups.Blank Con? trol Group (LG) : complete medium contain 1.4mmol/L glucose. Control group (LGC)：co-cultured nifedipine with medium in order to restain endogenous insulin release. Experimental group (LINS or HINS) add0.5U/L insulin or5U/L insulin on top of LGC. After being stimulated for0, 30, 60, 90, 120mins, proinsulin (PI) mRNA level were assessed by semi-quantitative RT-PCR. Insulin receptor substrate1(IRS1) tyrosine phosphorylation was detected by immunocytochemistry. Results (1) Expression of PI was up regulated by both LINS and HINS, and peak at60mins. (2) After stimulation for 30mins, the level of IRS1tyrosine phosphorylation in the experimental group was significantly higher than control group, and the peak time be? tween LINS and HINS was different. (3) Between group of LG and LGC, the expression of PI mRNA and IRS1tyrosine phos? phorylation show no difference.Conclusion Short term exogenous insulin stimulation can promote expression of proinsulin genes，which is concentration dependent. The expression and regulation of PI were related with IRS1signal transduction.

Key words: proinsulin, tyrosine phosphorylation