Estrogen helps women pile on pounds

Washington, Oct 6 (IANS) Women often pile on the pounds as they age, with estrogen - a sex hormone - playing an unsuspecting part in this process.

The finding potentially opens the way to developing highly selective hormone replacement therapies (HRT) to combat obesity or infertility in women, without inviting heart disease or breast cancer, says a new study.

'When women approach menopause, they gain weight in fat and their energy expenditure goes down,' says Deborah Clegg of the University of Texas Southwestern Medical Centre.

Estrogen levels decline and women grow increasingly susceptible to obesity and metabolic syndrome, says Clegg, who led the study, the journal Cell Metabolism reports.

Estrogen acts on receptors found throughout the body, in fat, on ovaries and in muscle. But when it comes to the hormone's influence on metabolism, Clegg suspected receptors in the brain, according to a Texas statement.

Others had traced the effects of estrogen on energy balance specifically to estrogen receptor-? (ER?). When her team deleted those receptors from the entire brains of mice, 'we got very, very fat mice', Clegg said. The animals consumed more calories and burned less.

The findings suggest that drugs developed to specifically target estrogen receptors in the brain might offer a useful alternative to HRTs that hit receptors throughout the body.