'Gluttony gene' stops mice feeling full

A mutation in a gene linked to obesity causes mice to eat up to 80 percent more than normal, a study suggests.

After eating, hormones send signals to the brain to let it know it's full. However, scientists found that in mice with a faulty version of the BDNF gene, these messages were 'blocked'.

'If there is a problem with the BDNF gene, neurons can't talk to each other, and the leptin and insulin [hormone] signals are ineffective, and appetite is not modified', said researcher Professor Baoji Xu from the Georgetown Medical Centre in the USA.

When the team monitored the eating habits of mice with and without the mutation, they found males were twice as heavy as their normal counterparts, and females were 2.7 times heavier. This was to do with them over-eating, rather than a reduction in their activity levels...