Oestrogen and energy allocation

Oestrogen is good for you. Oestrogen depletion leads to inactivity, unhealthy fat accumulation, and diabetes. In rodents, a preovulatory surge in 17β-oestradiol (oestrogen E2) temporarily allows energy expenditure to outpace energy intake, thus coordinating increased physical activity with peak sexual receptivity. To investigate how oestrogen affects energy allocation, Ingraham and colleagues examine oestrogen receptor alpha (ERα) signalling in the brain in female mice. In doing so they discover a small population of neurons that express melanocortin-4 receptor (MC4R), and which integrate oestrogen and melanocortin signals. The key finding is as follows -- these neurons send signals to arousal centres, showing how hormones trigger bursts in activity. What's more, bypassing the oestrogen-dependent gating of these neurons counteracts sedentary behaviour and sluggish metabolism associated with hormone depletion.