Objective Retinoic acid receptor related receptor α (RORα) is a nuclear receptor modulating physiopathological processes such as dyslipidemia, atherosclerosis, obesity and diabetes.RORα deficient mice display metabolic abnormalities and alterations in insulin sensitivity and glucose uptake.The aim of this study is to investigate if RORα regulates the expression and secretion of insulin.Methods Amplified rat Ins2 gene promoter was cloned into pGL3-Basic reporter vector.The cDNA encoding full-length mouse RORα was amplified by RT-PCR and then subcloned into the pAdTrack-CMV vector.INS-1 cells were infected with RORα-adenovrius or RORα shRNA plasmid.The expressions of RORα and Beta2 were detected by both real-time quantitative PCR and Western-blotting.The amount of insulin was measured by ELISA.The binding of RORα to insulin promoter was examined by electrophoretic mobility shift assay (EMSA).Results Endogenous Ins2 mRNA expression was up-regulated by overexpression of RORα in rat INS-1 cells.Knock-down of RORα by shRNA produced a decrease in Ins2 mRNA.Furthermore, the altered expression of RORα also led to the alteration of secreted insulin and cellular content insulin accordingly.In addition, we identified a functional RORα response element (RORE) within the Ins2 promoter.Manipulation of RORα levels through stable over-expression or shRNA knock-down also affected the level of transcription factor BETA2 in beta cells.BETA2 is a crucial factor for the assembly and function of the insulin gene transcription complex.Conclusion RORα modulates the insulin expression and secretion.RORα regulates insulin expression directly by binding to RORE in insulin promoter and indirectly by affecting the expression of insulin transactivator Beta2.