Western blot assay for determination of P450scc (A, C) and StAR (B, D) protein expression in Leydig cells. 1: normal control group; 2: Heshouwuyin control group; 3: aging group; 4: Shouwu pill group; 5: Heshouwuyin group. NCG: normal control group; SWYC: Heshouwuyin control group; AG: aging group; SWPG: Shouwu pill group; SWYG: Heshouwuyin group. Each histogram represents the mean ± SD of the values for 5 rats. Columns with different letters represent statistically different values, while same letters indicates no significant difference.