Under normal conditions, insulin causes a receptor in the brain of a fruit fly to release something called juvenile hormone. This second hormone triggers rapid ageing and reproduction. When Dr Tatar and his colleagues bred fruit flies with faulty receptors, the flies lived much longer. This is the first evidence of the way this ageing mechanism works. The discovery might not be an immediate answer to those wanting to add a few years to their lifespan, however.
Fruit flies are common subjects for biologists as they breed quickly There are side effects.
Many of the flies with the faulty receptor remained very small. Dr Tatar said the findings could lead to more studies on species like mice. We'd also like to study how juvenile hormone regulates body ageing. More evidence A team at University College London, UK, has also been trying to find out if the effects of hormones in C. elegans extend to other species, or even humans. But, as might possibly be expected from a process linked not only to ageing but also to reproduction, some of the flies were much less fertile.