Figure 2: Effects of annexin A5 (A5) on the mRNA and protein expression of StAR and testosterone synthesis-related enzymes in rat Leydig cells. ( a ) Cells were treated with 1 nmol l−1 annexin A5 for 24 h, and the mRNA expression of StAR, P450scc, 3-HSD, CYP17A, and 17-HSD10 was examined by semi-quantitative RT-PCR. Rpl19 was used as an internal control. ( b ) The protein expression of StAR, P450scc, 3β-HSD, and 17β-HSD was detected by Western blotting. Quantitation of StAR, P450scc, 3β-HSD, and 17β-HSD expression was determined by the normalization to the internal control β-actin. All data represent mean ± s.d. from at least three independent experiments. *P < 0.05, **P < 0.01, compared with the control.