From innovations report: "Underfeeding an organism such as the ordinary roundworm alters its endocrine function, which regulates hormones instrumental in metabolism. But no connection between the longevity induced by calorie restriction and the endocrine system has been found - until now. ... a particular pair of neurons in the heads of underfed worms may play an essential role in their lengthy lives. When these two individual neurons were killed by a laser beam, the worms could not enjoy the longevity normally associated with calorie restriction. ... skn-1 genes expressed only in these two cells support dietary-restriction longevity; without the genes, the longevity increase on dietary restriction disappeared ... We suspect that the two neurons sense dietary restriction and secrete a hormone that increases metabolism - and life span - in the animal. ... calorie restriction activates the silenced information regulator (SIR2) gene, which has the apparent ability to slow aging. This gene makes a protein called Sir2, which Guarente has shown is integrally tied to extending life span in yeast and in the roundworm. Humans carry a similar gene. How Sir2 relates to the two neurons identified in the findings is not yet clear ... Guarente suggests that the first commercial products based on manipulating Sir2 to slow aging will appear in the next 10 to 20 years. It is only a matter of time, he said, before aging itself is declared a disease."