Metformin induces a prompt decrease in LH-stimulated testosterone response in women with PCOS independent of its insulin-sensitizing effects.

Background: The use of insulin-sensitizing drugs has been shown to improve both the reproductive and the metabolic aspects of PCOS. However, the mechanisms by which metformin exerts its effects in PCOS are still not completely understood. There is growing evidence of a direct effect of metformin on ovarian steroidogenesis, independent of its effects on insulin sensitivity.

Metformin, naltrexone, or the combination of prednisolone and antiandrogenic oral contraceptives as first-line therapy in hyperinsulinemic women with polycystic ovary syndrome.

To compare the short-term effects of metformin (M), naltrexone (N), and a combination of OC and prednisolone (OC/Pr) on the metabolic state and the ovarian function of PCOS women, we randomized 29 women to a 3-month course of therapy. We observed significant improvements in hyperandrogenemia and ovulation rates in PCOS women of all three groups, in the absence of changes in the metabolic state, suggesting that insulin resistance in PCOS patients is only one of several factors leading to hyperandrogenemic ovarian failure.