Meanwhile, the Cyp17a1 mRNA expression is shown in Figure 5B. Letrozole induction caused Cyp17a1 mRNA expression to be upregulated significantly (p < 0.05) in untreated PCOS rats compared with normal control rats (4.93 ± 0.13 vs. 1.00 ± 0, p < 0.05). Here, CYP17A1 is linked to polycystic ovary syndrome.