Role of hypothalamic neuropeptide Y in feeding and obesity.

The 36-amino-acid peptide, neuropeptide Y (NPY), is the most abundant peptide in the rat brain. When administered into the brain, NPY produces a variety of physiological actions including a pronounced stimulation of feeding in satiated rats. Elevations in hypothalamic NPY have been reported after food deprivation and in genetically obese rodents. NPY is believed to produce its actions through a portfolio of G-protein coupled receptors, Y1, Y2, Y4 and Y5. Studies using peptide analogs, receptor knockout animals and specific receptor antagonists suggest the Y1 and Y5 receptors are important in mediating the effects of NPY on food intake in rats. Development of specific receptor antagonists with improved pharmacokinetic properties will be required to determine the importance of NPY in human obesity and appetite disorders.