Abstract: Objective：To explore the effect of CALB2 on steriodogenesis in testicular Leydig cell，we firstly established LV-calb2 and LV-siRNA-calb2 lentivirus vectors. Methods：Firstly，the over-expression and interference plasmids were synthysized，and the bacterial competent cells were prepared ahead. Secondly，polymerase chain reaction（PCR） and gene sequencing were administered to ensure the LV-calb2 and LV-siRNA-calb2 lentivirus vectors constructed successfully. At last，the infection efficiency was tested and then the level of testosterone in MLTC-1 and the level of progesterone in R2C were measured by radioimmunaossay after MLTC-1 and R2C were infected with LV-calb2 and LV-siRNA-calb2 respectively. Results：PCR and gene sequencing confirmed that LV-calb2 and LV-siRNA-calb2 lentivirus vectors were established，with the capacity to infect efficiently MLTC-1 and R2C. Testosterone production was significantly increased in the MLTC-1 infected with LV-calb2 （P＜0.001）, while progesterone production was significantly decreased in R2C infected with LV-siRNA-calb2（P＜0.05）. Conclusions：This study successfully constructed LV-calb2 and LV-siRNA-calb2 lentivirus vectors which could infect Leydig cells with high-efficiency. The preliminary result indicated that CALB2 promoted steriodogenesis in Leydig cells.

Key words: Calcium-binding protein, vitamin D-dependent, Lentivirus, Testis, Leydig cells, Androgens