Plays a role in the regulation of food intake and energy metabolism (PubMed:29116147). May also be involved in suppressing the anxiety response by promoting the expression of serotonin-related genes such as fev, tph2 and slc6a4a (PubMed:31474838). Acts as a ligand for galanin receptors galr2a and galr2b (PubMed:24517231). Brain administration of the peptide inhibits food consumption and elevates levels of glucose, triacylglycerol and cholesterol in the serum (PubMed:29116147). Likely to control food intake by regulating appetite related genes which includes the negative regulation of the orexigenic factor agrp (PubMed:29116147). By controlling food intake it may act as a satiety factor in energy metabolism (PubMed:29116147). Mainly expressed in the brain and ovary (PubMed:23623870, PubMed:24517231). Detected bilaterally in the adult brainstem (PubMed:30903017). Expressed in neurons in the dorsal habenula (dHb) (PubMed:31474838, PubMed:30903017). In the dHb some neurons project into the interpeduncular nucleus (IPN) where expression often overlaps with galr2a and galr2b (PubMed:31474838, PubMed:30903017). Weakly expressed in the liver, intestine, kidney, heart and gill (PubMed:23623870). In embryos, first detected at the 1 cell stage but disappears by the 2 cell stage (PubMed:30903017). Expressed again from 24 hours post fertilization (hpf) (PubMed:30903017). At 24 hours post fertilization (hpf), detected in a few cells in the embryo hindbrain (PubMed:30903017). In larvae, expressed in the neurons and nerve fibers of the midbrain tegmentum and hindbrain (PubMed:30903017). In the hindbrain, expressed in reticulospinal neurons with spinal projections (PubMed:30903017). Axons of hindbrain neurons project into the dorsal spinal cord where expression often overlaps with galr2b (PubMed:30903017). In larvae, not detected in the hypothalamus and not detected outside of the brain (PubMed:30903017). Up-regulated during folliculogenesis. Belongs to the spexin family.