‘Greedy gene’ that makes you eat more even when you are full is uncovered by scientistsCould lead to treatments for obesity
19:28 GMT, 18 March 2012
The secret to staying slim may be all in your genes.
Scientists believe they have found the ‘gluttony gene’ which fails to tell your brain when you are full.
In tests on mice, they showed that a mutation on a single gene broke down communication in the body and led to non-stop eating and rapid weight gain.
Gut buster: Scientists believe they have uncovered a gene which makes you eat even when are full because it breaks down communication between the body and the brain
But the good news is, they hope identifying the gene could help with treatments for obesity which affects nearly one in four adults in the UK.
Researchers at Georgetown University Medical Centre in the U.S. studied variations in the Bdnf gene in mice.
Humans also have this gene and it has been linked to obesity, but the researchers say it was not clear until now exactly how it worked.
After a meal, the activity of this gene transmits chemical signals down a chain of brain cells until they reach the hypothalamus, which receives the message that you are full and suppresses the appetite.
Breakthrough It is hoped the discovery will lead to treatments for obesity
However, in mice which had a mutation of this gene, these chemicals – leptin and insulin – were not being transmitted to their target, and they ate twice as much as those without the mutation.
Lead researcher Dr Baoki Xu said: ‘This discovery may open up novel strategies to help the brain control body weight.’
His team found the Bdnf gene has ‘short’ and ‘long’ versions which form at an early stage in the womb.
Those with the ‘long’ form successfully sent the chemical signals to say ‘I’m full’ through a ‘superhighway’ of neurons in the brain to the hypothalamus.
However in those with the short form, the signals reached some brain cells but could not be picked up by the dendrites – the branch-like ‘fingers’ coming out of the cells which pass messages on to the right place.
Dr Xu said: ‘If there is a problem with the Bdnf gene, neurons can’t talk to each other, and the leptin and insulin signals are ineffective and the appetite is not modified.’
The hypothalamus is involved in learning and memory. Previous work has shown mice without the ‘long’ version of this gene also had memory problems.
Link: Humans also have the Bdnf gene which researchers have identified in mice as causing rapid weight gain
Scientists will now be looking at whether the faulty transmission line can be modified, to help prevent and treat obesity, the researchers wrote in the journal Nature Medicine (KEEP).
Dr Xu said drugs which could stimulate Bdnf activity in the brain was the next step. He said: ‘We have opened the door to both new avenues in basic research and clinical therapies, which is very exciting.’
Tam Fry, spokesman for the National Obesity Forum said yesterday that the researcher were ‘on the right track’ in believing that getting leptin messages to the brain could be the key to suppressing appetite.
But he said:‘Many others on the same track hoping to find the magic treatment to prevent or cure obesity.
‘Understandably Xu is excited having got as far as he has but fixing the mutation may not be plain sailing.
'Even when its fixed in mice it will be years before his solution can he be used in humans.’