Abstract: Objective To explore the effect of Heshouwuyin on the expression of P450 side-chain cleavage enzyme(P450scc) and steroidogenic acute regulatory protein (StAR) in testis tissue of rats with exercised-induced fatigue. Methods Sixty SD rats were randomly divided into 6 groups,10 rats in each group, including a normal control group(group A), a Heshouwuyin administered normal group(group B),a model control group(group C), a spontaneously recovering group(group D), a Heshouwuyin treated group (group E), and a Heshouwuyin prevented group (group F). Groups C, D, E and F were exercised-induced fatigue animal model, groups in which animals were administrated Heshouwuyin ［20g/(kg.d), contained crude drug 4.8kg/L］. Animals in group F were administrated Heshouwuyin before modeling, and animals in group E were treated with Heshouwuyin for 60 days after success of modeling. Beckmancoulter Unicel Dxl 800 was used to detect the level of serum testosterone, according to the manufacture’s instructions. Western blotting and RT-PCR were used to observed the differential expression of P450scc and StAR. Result P450scc protein was expressed in Leydig cells and spermatocyte. Compared with group A, the expression of P450scc protein and mRNA in group C decreased ( P <0.05), and the expression of P450scc protein and mRNA in groups B and F increased more than E, D, A. StAR protein was expressed in Leydig cells. Compared with group A, the expression of StAR protein and mRNA in group C decreased ( EM>P/EM> <0.05), and the expression of StAR protein and mRNA in groups E and F increased more than A, D, but there was no difference between groups A and D ( EM>P/EM> ＞0.05). Conclusion Th

Key words: Heshouwuyin, Exercise-induced fatigue, Testosterone, P450 sidechain cleavage enzyme （P450scc）, Steroidogenic acute regulatory protein （StAR）, Western blotting, Immunohistochemistry, Rat