ESR2 and polycystic ovary syndrome: Treatment with clomiphene (0.49 ± 0.03), KH + clomiphene (0.47 ± 0.04), KH + metformin (0.39 ± 0.03), metformin (0.38 ± 0.03), and KH only (0.37 ± 0.03) significantly upregulated ERβ mRNA expression (p < 0.05) compared with the untreated PCOS group (0.07 ± 0.01).