Serum leptin changes with metformin treatment in polycystic ovarian syndrome: correlation with ovulation, insulin and testosterone levels

The relationship between leptin, insulin resistance and other hormonal parameters in polycystic ovarian syndrome (PCOS) is controversial. We investigated the effect of metformin on leptin levels in women with PCOS. Thirty women with PCOS received metformin 500 mg thrice a day. After two months of metformin treatment the mean leptin levels reduced significantly (p < 0.001). Ovulation was achieved in 28 patients, who also had a significant reduction in leptin levels (p < 0.001). Leptin showed significant positive correlation with weight (p < 0.05) and testosterone (p < 0.01), but no significant correlation with insulin. It is concluded that metformin reduces leptin resistance in PCOS women which induces ovulation. Leptin shows a significant correlation with testosterone and not with insulin.