The study found that women with PCOS who are overweight have lower blood levels of kisspeptin (also called metastin) and that these lower levels are linked to higher insulin resistance and higher free androgen hormones. In contrast, leaner PCOS women and overweight women without PCOS had higher kisspeptin levels. The data suggest that insulin resistance and excess androgens may suppress kisspeptin production.

This study was designed to: [1] measure, for the first time, metastin (kisspeptin) levels in women with polycystic ovary syndrome (PCOS), a condition associated with hypersecretion of LH and hyperandrogenemia; and [2] investigate the possible correlations between metastin and PCOS-related reproductive and metabolic disturbances. Clinical study. University hospital. Twenty-eight obese and overweight (body mass index [BMI] >25 kg/m2) women with PCOS, 28 normal weight (BMI <25 kg/m2) women with the syndrome, and 13 obese and overweight controls (ovulatory women without clinical or biochemical hyperandrogenemia) were selected. Blood samples were collected between day 3 and day 6 of a spontaneous bleeding episode in the PCOS groups and a menstrual cycle of the controls, at 9:00 AM, after an overnight fast. Circulating levels of LH, FSH, PRL, T, Delta4-androstenedione (A), DHEAS, 17alpha-OH-P, sex hormone-binding globulin (SHBG), insulin, glucose, and metastin were measured. Both normal weight women with PCOS and obese controls were less insulin resistant and had significantly higher metastin levels, compared to obese and overweight women with the syndrome. Plasma kisspeptin levels were negatively correlated with BMI, free androgen index, and indices of insulin resistance. These results indicate that metastin is negatively associated with free androgen levels. The PCOS-associated insulin resistance and consequent hyperinsulinemia probably contribute to this effect by [1] stimulating androgen synthesis by the polycystic ovary (PCO) and [2] suppressing SHBG production in the liver.