The expression levels of Cytochrome P450 family 11 subfamily a member 1 (Cyp11a1), 3β-hydroxysteroid dehydrogenase (Hsd3b) and Steroidogenic acute regulatory protein (StAR) proteins related to steroid hormone biosynthesis signaling pathway were decreased in the PCOS group, and levels were increased in the NaBu group except Hsd3b; whereas Cytochrome P450 family 17 subfamily a member 1(Cyp17a1) was upregulated in the PCOS rats and reduced in the NaBu rats. This evidence concerns the gene CYP17A1 and polycystic ovary syndrome.