Short-term oral oestrogen therapy dissociates the growth hormone/IGF-I axis without altering energy metabolism in premenopausal women

Objective: Oral oestrogen has been shown to dissociate the growth hormone (GH)/insulin-like growth factor (IGF)-I axis and alter energy metabolism in postmenopausal women. This study was designed to determine whether these metabolic changes occur with short-term oral oestrogen in premenopausal women. Study design: A double-blind placebo controlled randomised-crossover design study was performed in 12 premenopausal women. Investigations were performed after either 5 days of oral 17β-oestradiol valerate 2 mg twice daily or placebo. Outcomes included body composition measured by bio-impedance, energy metabolism measured by indirect calorimetry and blood sampling. Results: Oral oestrogen significantly suppressed IGF-I levels and increased fasting GH levels. No significant changes in energy metabolism or body composition were detected. Conclusions:Short-term oral oestrogen suppresses IGF-I and elevates GH levels in premenopausal women. No effects were seen on body composition and energy metabolism. Further research is required to determine whether metabolic effects of oral oestrogen may become apparent if longer courses of treatment were administered to premenopausal women.