Relationships between circulating leptin concentrations and other hormonal parameters in obese and non-obese women with polycystic ovary syndrome.

To clarify the role of leptin in women with polycystic ovary syndrome (PCOS), we analyzed whether serum leptin levels correlate with other hormonal parameters in obese and non-obese women with PCOS. We studied 20 obese (body mass index, BM ≥25 kg/m) and 20 non-obese (BMI <25 kg/m) women with PCOS diagnosed by the existence of menstrual disturbance, elevated serum level of luteinizing hormone (LH) with normal follicle-stimulating hormone (FSH) and the characteristic polycystic appearance of the ovaries on transvaginal ultrasound images. Blood samples for LH, FSH, estradiol, testosterone (T), androstenedione (Δ) and leptin were obtained, and the relationships between variables were examined by calculating Spearman correlation coefficients. Mean levels of leptin, T and Δ in obese PCOS women were significantly higher than those in non-obese PCOS women, but this was not the case for BMI, bodyweight and waist to hip ratio. In all the 40 PCOS women considered together, there were significant positive correlations of leptin with BMI, waist to hip ratio, and Δ levels. However, in each group separately, serum leptin levels in obese PCOS women correlated only with BMI and bodyweight, whereas serum leptin levels in non-obese PCOS women correlated with serum A4 levels. Although further study is needed to assess the role of leptin on ovarian function in non-obese women with PCOS, present findings do not support the fact that leptin is involved in the development of hormonal abnormalities in obese women with PCOS. (Reprod Med Biol 2002; : 49-54).