Effects of metformin on serum insulin and anti-Mullerian hormone levels and on hyperandrogenism in patients with polycystic ovary syndrome.

To evaluate the relationship between serum anti-Mullerian hormone levels (AMH) and insulin resistance (IR) before and after meformin treatment and to compare AMH levels of polycystic ovary syndrome (PCOS) women in the early follicular phase. Twenty PCOS women with IR, taking metformin 1500 mg/day for 8 weeks, and 16 non-PCOS controls were enrolled in this longitudinal study. Serum levels of AMH, insulin, glucose, testosterone, and quantitative insulin check index (QUICKI), were assessed before and after treatment in PCOS group. AMH levels were higher in untreated PCOS (p < 0.0001), as were luteinizing hormone (LH) (p = 0.0004), testosterone (p = 0.0017) as well as 17-hydroxyprogesterone (p = 0.03). PCOS women show positive correlation between AMH and testosterone (R = 0.83; p < 0.0001) only prior to treatment. Metformin treatment, lead to a significant decrease in serum insulin (p = 0.0132) and testosterone (p = 0.0017) levels. However, no alteration in AMH levels was observed after treatment. Despite the improvement of metabolic parameters and the reduction of androgen levels, AMH levels did not change after metformin treatment. Maybe, the dose, and possibly the time of use, of metformin are factors associated with the reduction of AMH levels.