Plays a role in controlling food intake and regulating body size. Stage 17 embryos show expression in the two brain hemispheres (neural cells located in the dorsal posterior region), the connected ventral ganglion (pairs of neural cells along the ventral midline) and the peripheral nervous system (expressed in the antennal-maxillary sensory cells). In the brain hemispheres of the feeding third instar larva, expression in neural cells is located in the dorsal-anterior region of the protocerebrum. In the larval ventral ganglion, expression is seen in the neural cells located in the subesophagial region, along the ventral midline and in thoracic and abdominal segments. In the adult brain, expression is seen in the medulla and the mushroom body calyx (at protein level). Expressed throughout development from embryo to adult. Flies overexpressing sNPF are heavier and bigger than wild-type. But loss-of-function flies are not smaller than wild-type. Belongs to the NPY family. Probable cloning artifact.