Research adds weight to fat burning theories

Monash University researchers have shown the hormone leptin may play a larger role in burning energy in the human body than was previously thought and could hold the key to new weight loss therapies.

Leptin is produced by fat and circulates in the blood to provide a signal to the brain informing the level of energy stores. It is already known to act on the brain to reduce appetite and to increase energy use through a process called thermogenesis.

Now the scientists have discovered leptin not only triggers thermogenesis in some fat cells -- which make up less than one percent of body mass - but that it also triggers the same response in muscle tissue, which makes up more than one third of body mass.

This has significant repercussion for the development of weight loss strategies.

It means leptin or a leptin mimic could trick the body into weight loss bysimply harnessing the body's natural process of thermogenesis.

The breakthrough has been made by Dr Belinda Henry and Professor Iain Clarke from the Department of Physiology in the Faculty of Medicine, Nursing and Health Sciences and colleagues.

"Now that we have shown leptin increases energy utilisation in muscle tissue, the potential for the hormone to have a positive impact has been greatly magnified. We can now start to re-create and enhance this natural process for the purposes of assisting weight loss," Dr Henry said.

"When combined with lifestyle changes, it could be a significant step forward in addressing the growing obesity problem in our community."

Prof Clarke said the challenge would be to trick the brain into triggering the response, as the hormone leptin is already higher in people who are overweight and the impact of the hormone is somehow reduced in the human body.

"The design of Leptin-mimic drugs which have the same effect is the next step for scientists," Prof Clarke said.

The research paper has been published in the latest edition of the Endocrinology Journal.

(Source: Endocrinology Journal: Monash University: March 2008)