Injections of a hormone made by fat cells can jump-start an idling reproductive system, research shows. Twice-daily injections of leptin restored menstruation in female athletes who had become so lean that their periods had stopped.
The Beth Israel Deaconess Medical Center team said the injections might also prevent bone loss and treat the eating disorder anorexia nervosa.
Their findings are reported in the New England Journal of Medicine.
Leptin is known to regulate appetite and weight and tells the brain how much energy is available in the body. It’s role in obesity has already been studied.
Leptin is made by the body’s fat and, therefore, women who are particularly thin, such as athletes with rigorous training programmes or women on very restrictive diets, produce less leptin.
In extreme cases, the woman’s body enters a state of ‘negative’ energy balance and her reproductive system shuts down to prevent a pregnancy and conserve energy.
This is called hypothalamic amenorrhoea or dysfunction.
These women also risk bone loss because of the resultant lack of female hormones, which can lead to osteoporosis and an increased risk of fractures.