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Diminished Metabolic Responses to Centrally‐Administered Apelin‐13 in Diet‐Induced Obese Rats Fed a High‐Fat Diet
Author(s) -
Clarke K. J.,
Whitaker K. W.,
Reyes T. M.
Publication year - 2009
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.2008.01815.x
Subject(s) - apelin , medicine , endocrinology , adipokine , respiratory exchange ratio , hypothalamus , obesity , receptor , diet induced obese , biology , leptin , heart rate , blood pressure , insulin resistance
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.