SYDNEY - AUSTRALIAN scientists have found how to switch hunger on and off using a molecule that targets the brain - a discovery which could stop weight loss in terminally ill patients or produce weight loss in the morbidly obese.

The molecule, known as MIC-1, is produced by common cancers and targets receptors in the brain that switch off appetite.

But Australian researchers found that by using antibodies against MIC-1 they were able to switch appetite back on.

When normal and obese mice were treated with MIC-1 they ate less and lost a lot of weight, suggesting that MIC-1 may also be used to treat severe obesity, said the Sydney researchers in a statement received on Tuesday.

'This work has given us a better understanding of the part of the brain that regulates appetite,' said Dr Herbert Herzog, director of neuroscience research at the Garvan Institute in Sydney.

'Our bodies send complex chemical signals to our brains, which interpret them and send back responses, in this case eat or don't eat. Our research indicated that MIC-1 is a previously unrecognised molecule sending a don't eat signal to the brain,' Dr Herzog said.

The researchers said it was hoped that in the near future, the MIC-1 findings will prevent a sizeable proportion of advanced cancer patients from 'literally wasting away'.

Dr Sam Breit at St Vincent's Centre for Immunology, who originally cloned the MIC-1 gene, said he believed the findings could have a significant impact on a range of appetite-related disorders.

'Injecting mice with MIC-1 protein also made them stop eating, suggesting that it may be possible to use this to advantage for treating patients with severe obesity,' he said.

The MIC-1 findings were published in the latest Nature Medicine magazine and the team of researchers led by St. Vincent's Hospital in Sydney hope to develop a human antibody and run clinical trials in the next few years. -- REUTERS