Sensing nutrients from within

Abstract

In mammals, feeding is in part regulated by sensors in internal organs, including the brain, that detect nutrients. Some of these internal sensors seem to be taste receptors, and this study indicates that the same is true in flies. The authors identified gustatory receptor 43a (Gr43a) as a fructose receptor in taste neurons and showed that it is also expressed in the fly brain. They found that brain Gr43a is needed to sense hemolymph fructose, which was shown to be a marker of nutritious carbohydrate intake, and that Gr43a activity promotes feeding in hungry flies but inhibits feeding in satiated flies.