The 36-amino-acid peptide, neuropeptide Y (NPY), is the most abundant pepti
de in the rat brain. When administered into the brain, NPY produces a varie
ty of physiological actions including a pronounced stimulation of feeding i
n satiated rats. Elevations in hypothalamic NPY have been reported after fo
od 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 speci
fic receptor antagonists suggest the Y1 and Y5 receptors are important in m
ediating the effects of NPY on food intake in rats. Development of specific
receptor antagonists with improved pharmacokinetic properties will be requ
ired to determine the importance of NPY in human obesity and appetite disor
ders. (C) 1999 Harcourt Publishers Ltd.