Dieters are often advised to ‘listen to their body’ so they’re more aware of being full, but what happens if the ‘full’ signal gets disrupted? When fat cells get bigger they produce leptin which acts a signal for the brain to turn off hormones that stimulate appetite and turn on hormones that suppress it. When working properly this keeps body weight within fairly narrow limits. The biochemistry behind this is not fully understood but researchers have found that a gene called AC3 is involved. Mutant mice that lack AC3 (right) can’t interpret messages from fat cells properly so their brain thinks that they’re starving. This leads to their brain sending signals to eat more and exercise less, causing the mice to get fat. Variation in this gene is also associated with obesity in humans and scientists hope that a deeper understanding of the process will lead to novel therapies.
Written by Julie Webb
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