Serum leptin levels and body weight in postmenopausal women under transdermal hormone replacement therapy

Leptin, the adipocyte-specific product of the ob gene, is implicated in body weight regulation and energy balance. We investigated the influence of hormone replacement therapy (HRT) on the body mass index (BMI) and serum leptin levels in 20 postmenopausal, nonobese women treated with transdermal HRT (delivery rate 50 microg 17beta-estradiol/24 h, 1 patch per week) for 6 months. Serum leptin levels were measured by ELISA and results were compared by means of the Student's paired t-test or Pearson's correlation. The mean patient age was 55+/-6.04 years. The mean body weight prior to the start of the study was 69.39+/-9.37 kg, and the BMI before HRT was 26.92+/-4.47 kg/m2. Both parameters remained unchanged under therapy. No significant change in absolute serum leptin values (18.8+/-8.4 ng/ml; 20.47+/-9.7 ng/ml; 17.92+/-8.7 ng/ml at 0, 4 and 6 months respectively) or in adiposity-corrected values (serum leptin/BMI) (0.68+/-0.24; 0.75+/-0.29; 0.67+/-0.26 at 0, 4 and 6 months respectively) were found. Serum leptin levels correlated well with BMI (r = 0.7193, p<0.0001). There was no significant correlation of estradiol with serum leptin levels before or during therapy. In summary, low dose, transdermal HRT exhibited no influence on serum leptin levels or BMI in postmenopausal women. These data suggest that low dose HRT does not influence body weight regulation in postmenopausal women.