Abstract: Objective To study the expression levels of LRP16 protein in 3T3-L1 preadipocyte differentiation and the effect of insulin on LRP16 protein expression in LRP16 cells.Methods 3T3-L1 preadipocytes were cultured in vitro and differentiated into matured adipocytes,then protein samples were collected everyday（0-8d）.Insulin was added into the culture medium of adipocytes for 24h at different concentrations（0,1,10,100nmol/L）,and then protein samples were collected.Expression levels of LRP16 protein in 3T3-L1 cells were measured by Western blot.Results LRP16 protein was not expressed or very weakly expressed in preadipocytes.The expression level of LRP16 protein increased rapidly from the day 3 or day 4 and reached its peak on day 7（P＜0.01） and then maintained there.No statistical difference was observed in expression of LRP16 protein on days 6-8（P＞0.05）.The insulin concentration was negatively correlated with the expression level of LRP16 protein in adipocytes after stimulated by insulin for 24h（P＜0.01）.Conclusion LRP16 protein expression level increases with the differentiation of 3T3-L1 adipocytes,gradually reaches its peak and then maintains there.Insulin down-regulates the expression of LRP16 protein in adipocytes.