Galanin-like peptide in the brain: effects on feeding, energy metabolism and reproduction

The hypothalamus plays an important role in the regulation of feeding behavior, energy metabolism and reproduction. A novel peptide containing 60 amino acid peptide and a non-amidated C-terminus is produced in the hypothalamic arcuate nucleus (ARC) and has been named galanin-like peptide (GALP) on the basis of a portion of this peptide being homologous with galanin. It acts in the central nervous system (CNS), where it is involved in the regulation of feeding behavior. GALP-producing neurons make neuronal networks with several feeding related peptide-producing neurons. Since GALP is involved in the control of food intake and energy balance, it is possible that it plays an important role in the development of obesity. Furthermore, GALP regulates plasma lateral hypothalamus (LH) levels via the activation of gonadotropin-releasing hormone (GnRH)-producing neurons, suggesting that GALP is active in the reproductive system. Thus, interesting findings on the roles of GALP have made across a number of physiological systems. This review will attempt to summarize the research carried out to date on these areas. Because GALP may be involved in feeding behavior, energy metabolism and reproduction, further studies on the morphology and function of GALP-containing neurons in the CNS should increase our understanding of the role of GALP in brain function.