Diminished metabolic responses to centrally-administered apelin-13 in diet-induced obese rats fed a high-fat diet

J Neuroendocrinol. 2009 Feb;21(2):83-9. doi: 10.1111/j.1365-2826.2008.01815.x. Epub 2008 Dec 6.


The central administration of apelin, a recently identified adipokine, has been shown to affect food and water intake. The present study investigated whether body weight could affect an animal's response to apelin. The effects of centrally-administered apelin-13 on food and water intake, activity and metabolic rate were investigated in adult male diet-induced obese (DIO) rats fed either a high fat (32%) or control diet. Rats were administered i.c.v. apelin-13, 15-30 min prior to lights out, and food and water intake, activity and metabolic rate were assessed. Intracerebroventricular administration of apelin-13 decreased food and water intake and respiratory exchange ratio in DIO rats on the control diet, but had no effect in DIO rats on the high-fat diet. In an effort to identify potential central mechanisms explaining the observed physiological responses, the mRNA level of the apelin receptor, APJ, was examined in the hypothalamus. A high-fat diet induced an up-regulation of the expression of the receptor. Apelin induced a down-regulation of the receptor, but only in the DIO animals on the high-fat diet. In conclusion, we have demonstrated a diminished central nervous system response to apelin that is coincident with obesity.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apelin Receptors
  • Body Weight / drug effects
  • Cytokines / blood
  • Diet*
  • Dietary Fats*
  • Drinking / drug effects
  • Eating / drug effects
  • Energy Metabolism / drug effects*
  • Energy Metabolism / physiology
  • Hypothalamus / drug effects
  • Hypothalamus / metabolism
  • Insulin / metabolism
  • Intercellular Signaling Peptides and Proteins / administration & dosage
  • Intercellular Signaling Peptides and Proteins / pharmacology*
  • Leptin / blood
  • Male
  • Obesity / metabolism*
  • Plasminogen Activator Inhibitor 1 / blood
  • Rats
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*


  • Apelin Receptors
  • Aplnr protein, rat
  • Cytokines
  • Dietary Fats
  • Insulin
  • Intercellular Signaling Peptides and Proteins
  • Leptin
  • Plasminogen Activator Inhibitor 1
  • Receptors, G-Protein-Coupled
  • apelin-13 peptide