Effects of estrogen versus estrogen and progesterone on cortisol and interleukin-6.

OBJECTIVES: The purpose of this study was to compare the effects of 3 months of estrogen replacement therapy, estrogen plus progesterone replacement therapy and a placebo, on the resting cortisol and interleukin-6 (IL-6) levels in post-menopausal women. METHODS: Forty-three women were randomised to one of three treatment arms: estradiol 2mg/day (ERT), estradiol 2mg/day plus medroxyprogesterone acetate 5mg/day (HRT), or a placebo that was administered orally for 3 months. RESULTS: Cortisol levels showed a significant condition by intervention interaction. Post hoc tests showed that ERT significantly increased cortisol levels after treatment compared to baseline, while in the HRT group a trend toward increased cortisol was found. No changes were observed in IL-6 levels. CONCLUSIONS: Estrogen administration elevated cortisol levels, but this effect may be moderated by progestins. IL-6 was not altered by ERT or HRT, future studies should consider the interaction of cortisol increases on change in IL-6 expression.