title: NPY ablation in C57BL/6 mice leads to mild obesity and to an impaired refeeding response to fasting.
abstract: Neuropeptide Y (NPY) is an orexigenic (appetite-stimulating) peptide that plays an important role in regulating energy balance. When administered directly into the central nervous system, animals exhibit an immediate increase in feeding behavior, and repetitive injections or chronic infusions lead to obesity. Surprisingly, initial studies of Npy(-/-) mice on a mixed genetic background did not reveal deficits in energy balance, with the exception of an attenuation in obesity seen in ob/ob mice in which the NPY gene was also deleted. Here, we show that, on a C57BL/6 background, NPY ablation is associated with an increase in body weight and adiposity and a significant defect in refeeding after a fast. This impaired refeeding response in Npy(-/-) mice resulted in a deficit in weight gain in these animals after 24 h of refeeding. These data indicate that genetic background must be taken into account when the biological role of NPY is evaluated. When examined on a C57BL/6 background, NPY is important for the normal refeeding response after starvation, and its absence promotes mild obesity.
authors.affiliation: Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Segal-Lieberman
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Trombly
authors.forename: Viral
authors.initials: V
authors.lastname: Juthani
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wang
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Maratos-Flier
mesh_terms: D000273:Adipose Tissue / Q000502:physiology; D000818:Animals; D001823:Body Composition / Q000235:genetics / Q000502:physiology; D004032:Diet; D004435:Eating / Q000235:genetics / Q000502:physiology; D005215:Fasting / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000502:physiology; D009478:Neuropeptide Y / Q000235:genetics / Q000502:physiology*; D009765:Obesity / Q000235:genetics*; D010101:Oxygen Consumption / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012727:Sex Characteristics
chemical_list: D009478:Neuropeptide Y