Suppressing sex hormones in women for 1 week reduces resting energy expenditure (REE). The effects of more chronic suppression on REE and other components of total energy expenditure (TEE), and whether this is specifically due to loss of estradiol (E2), are not known. We compared the effects of 5 months of sex hormone suppression (gonadotropin releasing hormone agonist therapy, GnRHAG) with placebo (GnRHAG+PL) or (GnRHAG+E2) add-back therapy on REE and the components of TEE. Premenopausal women received GnRHAG (leuprolide acetate 3.75 mg/mo) and were randomized to receive transdermal therapy that was either (E2) (0.075 mg/d; n=24; mean±SD, aged=37±8 yr, BMI=27.3±6.2 kg/m2) or placebo (n=21; aged=34±9 yr, BMI=26.8±6.2 kg/m2). REE was measured using a metabolic cart, and TEE, sleep EE (SEE), exercise EE (ExEE, 2 x 30 min bench stepping), non-Ex EE (NExEE), and the thermic effect of feeding (TEF) were measured using whole-room indirect calorimetry. REE decreased in GnRHAG+PL [mean (95% CI), -54 (-98, -15) kcal/d], but not GnRHAG+E2 [+6 (-33, +45) kcal/d)] (difference in between-group changes, P<0.05). TEE decreased in GnRHAG+PL [-128 (-214, -41) kcal/d] and GnRHAGAG+E2[-96 (-159, -32) kcal/d], with no significant difference in between-group changes (P=0.55). SEE decreased similarly in both GnRHAG+PL [-0.07 (-0.12, -0.03) kcal/min)] and GnRHAG+E2 [-0.07 (-0.12, -0.02) kcal/min)]. ExEE decreased in GnRHAG+PL [-0.46 (-0.79, -0.13) kcal/min)], but not GnRHAG+E2 [-0.30 (-0.65, +0.06) kcal/min]. There were no changes in TEF or NExEE in either group. In summary, chronic pharmacologic suppression of sex hormones reduced REE and this was prevented by E2 therapy.
- pre-menopausal women
- room calorimetry
- resistance exercise
- gonadotropin releasing hormone
- Copyright © 2015, Journal of Applied Physiology