title: Acute central neuropeptide Y administration increases food intake but does not affect hepatic very low-density lipoprotein (VLDL) production in mice.
abstract: OBJECTIVE
  Central neuropeptide Y (NPY) administration stimulates food intake in rodents. In addition, acute modulation of central NPY signaling increases hepatic production of very low-density lipoprotein (VLDL)-triglyceride (TG) in rats. As hypertriglyceridemia is an important risk factor for atherosclerosis, for which well-established mouse models are available, we set out to validate the effect of NPY on hepatic VLDL-TG production in mice, to ultimately investigate whether NPY, by increasing VLDL production, contributes to the development of atherosclerosis.
  
  
  METHODS
  Male C57Bl/6J mice received an intracerebroventricular (i.c.v.) cannula into the lateral (LV) or third (3V) ventricle of the brain. One week later, after a 4 h fast, the animals received an intravenous (i.v.) injection of Tran(35)S (100 µCi) followed by tyloxapol (500 mg/kg body weight; BW), enabling the study of hepatic VLDL-apoB and VLDL-TG production, respectively. Immediately after the i.v. injection of tyloxapol, the animals received either an i.c.v. injection of NPY (0.2 mg/kg BW in artificial cerebrospinal fluid; aCSF), synthetic Y1 receptor antagonist GR231118 (0.5 mg/kg BW in aCSF) or vehicle (aCSF), or an i.v. injection of PYY3-36 (0.5 mg/kg BW in PBS) or vehicle (PBS).
  
  
  RESULTS
  Administration of NPY into both the LV and 3V increased food intake within one hour after injection (+164%, p<0.001 and +367%, p<0.001, respectively). NPY administration neither in the LV nor in the 3V affected hepatic VLDL-TG or VLDL-apoB production. Likewise, antagonizing central NPY signaling by either PYY3-36 or GR231118 administration did not affect hepatic VLDL production.
  
  
  CONCLUSIONS
  In mice, as opposed to rats, acute central administration of NPY increases food intake without affecting hepatic VLDL production. These results are of great significance when extrapolating findings on the central regulation of hepatic VLDL production between species.
authors: Department of General Internal Medicine, Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands.
authors: Janine J
authors: JJ
authors: Geerling
authors: Yanan
authors: Y
authors: Wang
authors: Louis M
authors: LM
authors: Havekes
authors: Johannes A
authors: JA
authors: Romijn
authors: Patrick C N
authors: PC
authors: Rensen
mesh_terms: D000758:Anesthesia; D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000378:metabolism; D003243:Consciousness / Q000187:drug effects; D004435:Eating / Q000187:drug effects*; D007276:Injections, Intraventricular; D008079:Lipoproteins, VLDL / Q000096:biosynthesis*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009478:Neuropeptide Y / Q000008:administration & dosage* / Q000494:pharmacology*; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D008079:Lipoproteins, VLDL; D009478:Neuropeptide Y