Correlation of leptin and sex hormones with endocrine changes in healthy Saudi women of different body weights

BACKGROUND: A relationship between estrogen and leptin has been described during the follicular phase of both spontaneous menstrual cycles and cycles stimulated with exogenous follicle-stimulating hormone (FSH), which suggest that leptin has either a direct effect on or is regulated by gonadal steroids in the human ovary. To examine the changes in plasma leptin levels during the menstrual cycle, we studied the association between plasma leptin and reproductive hormones in young, healthy Saudi women. SUBJECTS AND METHODS: Sixty-five young women between 19 to 39 years of age, with a normal menstrual cycle, were grouped into 33 overweight and obese females of BMI >25 kg/m(2), and 32 lean females of BMI <25 kg/m(2). Anthropometrics measurements were made at the time of the collection. Samples were analyzed for leptin, progesterone, estradiol (E(2)), FSH, luteinizing hormone (LH), cortisol, and testosterone concentrations. RESULTS: Overweight and obese women, compared with lean, tended to have a significantly higher plasma leptin levels (11.38± 4.06 vs. 6.22± 2.87 ng/mL; P=0.05). In overweight and obese subjects, circulating leptin concentrations showed a direct correlation with BMI (r=0.53; P=0.002), hip circumference (r=0.32; P=0.005), waist-hip ratio (r=0.37; P=0.042), weight (r=0.41; P=0.021), and E(2) on day 3 (r=0.35; P=0.048). In all correlation analyses, leptin levels did not correlate with cortisol or testosterone. In lean subjects, a bivariate correlation analysis showed that plasma leptin concentrations were directly correlated to hip circumference (r=0.43; P=0.012). Moreover, a direct correlation was found with progesterone on day 10 (r=0.43; P=0.014) and E(2) on day 24 (r=0.47; P=0.007). CONCLUSION: There is a link between plasma leptin and progesterone concentrations during the menstrual cycle, and the variation in circulating estradiol concentrations may have an influence on circulating leptin in female subjects.