Objective To observe the effect of exogenous insulin on the expression of P-glycoprotein (P-gp)and the secretion of insulin in pancreatic beta cells (INS-1 832/13).Methods Insulinoma cells (INS-1 832/13) were cultured with 0.5 μmol/L exogenous insulin for 30 days.MTT assay was used to measure cell viability.Quantitative RT-PCR and western blot were used to detect the expression of P-gp mRNA and protein respectively,and glucose stimulated insulin secretion (GSIS) were measured by radioimmunoassay.Results Compared with control group,0.5 μmol/L exogenous insulin promoted the viability of INS-1 832/13 cells [(102.00±12.99) vs (356.00±35.51),P<0.05] and accelerated P-gp expression [(107.50±17.08) vs (307.50±44.25)] both at mRNA and protein levels [(105.00±12.91) vs (192.50±35.94),P<0.05].Glucose stimulated insulin secretion was positively correlated with P-gp expression level,but had no significant effect on basal insulin secretion.Conclusion Exogenous insulin can promote the secretion function of INS-1 832/13 cells,and the mechanism may be related to the expression of P-gp.