Abstract
Calorie restriction (CR), which is thought to be largely dependent on the neuroendocrine system modulated by insulin/insulin-like growth factor-I (IGF-I) and leptin signaling, decreases morbidity and increases lifespan in many organisms. To elucidate whether insulin and leptin sensitivities are indispensable in the metabolic adaptation to CR, we investigated the effects of CR on obese Zucker (fa/fa) rats and lean control (+/+) rats. CR did not fully improve insulin resistance in (fa/fa) rats. Nonetheless, CR induced neuropeptide Y (NPY) expression in the hypothalamic arcuate nucleus and metabolism related gene expression changes in the liver in (fa/fa) rats and (+/+) rats. Up-regulation of NPY augmented plasma corticosterone levels and suppressed pituitary growth hormone (GH) expression, thereby modulating adipocytokine production to induce tissue-specific insulin sensitivity. Thus, central NPY activation via peripheral signaling might play a crucial role in the effects of CR, even in insulin resistant and leptin receptor deficient conditions.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Arcuate Nucleus of Hypothalamus / metabolism
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Body Weight
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Caloric Restriction*
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Gene Expression Regulation
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Ghrelin / blood
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Gluconeogenesis / genetics
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Growth Hormone / genetics
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Growth Hormone / metabolism
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Hepatocyte Nuclear Factor 4 / metabolism
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Insulin / blood
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Leptin / blood
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Liver / metabolism
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Mitochondria / genetics
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Nerve Degeneration / chemically induced
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Nerve Degeneration / metabolism
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Neuropeptide Y / metabolism
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Obesity / metabolism*
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Oxidation-Reduction
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Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
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Pituitary Gland / metabolism
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Protein Binding
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RNA-Binding Proteins / metabolism
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Rats
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Rats, Zucker
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Receptors, Leptin / deficiency
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Receptors, Leptin / metabolism
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Thinness / metabolism*
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Transcription Factors / metabolism
Substances
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Ghrelin
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Hepatocyte Nuclear Factor 4
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Insulin
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Leptin
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Neuropeptide Y
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Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
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Ppargc1a protein, rat
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RNA-Binding Proteins
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Receptors, Leptin
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Transcription Factors
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Growth Hormone