CYP19A1 and polycystic ovary syndrome: Hyperleptinemia is significantly associated with PCOS and may lead to an increased free leptin index in young women. Increased leptin levels, along with other biochemical parameters, contribute to increased oxidative stress in adolescent girls with PCOS. The leptin signaling pathway plays a crucial role in the production of male hormones in women with PCOS. Leptin and insulin resistance mediate lower expression of aromatase in granulosa cells from women with PCOS.