Adiponectin R1 and R2 expression in MC3T3-E1 cells and effects of siRNA-AdipoR1 transfection. (A) Adiponectin receptor expression in MC3T3-E1 cells. Total RNA from the cells was subjected to RT-PCR. HPRT, house keeping gene, and AdipoR1 were visualized in a 2% agarose gel stained with ethidium bromide. AdipoR1 mRNA but not AdipoR2 was expressed in MC3T3-E1 cells, while both of them were expressed in 3T3-L1 cells, which were examined as a positive control. (B) Confirmation of the effect of siRNA-AdipoR1. The siRNA restrained only siAdipoR1, showing that its knock down effect was specific (p < 0.001). N; 0.2% BSA, TR; transfection reagent, CypB; transfection of siRNA-Cyclophilin B (CypB), control; transfection of non-targeting siRNA. (C) Confirmation of the effect of siRNA-CypB. (D) The durability of siRNA-AdipoR1. Total RNA was collected at 4, 7, 10 days after siRNA transfection. The knock down effect of siRNA-AdipoR1 was sustained as long as 10 days after transfection at the expression level of 14.9% of the control. Results are expressed as the mean ± SEM fold increase (n = 5) over control values. * p < 0.05, ** p < 0.01, *** p < 0.001.