Effects of administration of 17 beta-oestradiol on serum leptin levels in healthy postmenopausal women

OBJECTIVE Women have higher leptin levels than men at a certain degree of a diposity, The role of oestrogens in the regulation of serum leptin levels r emains inconclusive. The aim of the present study was to investigate the ef fect of unopposed oestrogen replacement therapy, during two months, on seru m leptin levels in postmenopausal women. DESIGN A double-blind, placebo-controlled, randomized study. SUBJECTS Twenty-five healthy postmenopausal women were studied (mean (+/- S D) age: 52.9 +/- 2.7 years, range of age: 48.7-57.4years; mean body mass in dex (BMI): 26.4 +/- 4.2 kg/m(2), range of BMI: 21.0-39.0 kg/m(2)). Twelve o f these women were treated with 2 mg 17 beta-oestradiol daily, and 13 postm enopausal women received placebo. MEASUREMENTS Before and at the end of a 2-month study period, anthropometri c and bio-electrical impedance measurements were performed, and fasting blo od samples were taken, to determine serum levels of sex hormones and leptin . RESULTS During the 2-month study period, body weight had increased signific antly in the placebo group compared with the treatment group, but no signif icant changes were observed in percentage of body fat or the amount of body fat in kg between the groups. Following administration of 17 beta-estradio l, the median leptin level increased from 17.6 mu g/l to 24.1 mu g/l after 2 months (P = 0.008 compared with baseline). This increase was significantl y different from the placebo group (P = 0.019), which showed no change in c irculating leptin levels. CONCLUSION This study demonstrates that unopposed oestrogen replacement the rapy during 2 months in postmenopausal women slightly, but significantly, i ncreases total serum leptin levels. This observation suggests a role for oe strogens in the regulation of leptin.