Critical effects of aging and nutritional state on hypothalamic neuropeptide Y and galanin gene expression in lean and genetically obese Zucker rats

Meena Jhanwar-Uniyal, Streamson C. Chua, Jr.

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

We have investigated, by Northern blot analysis, the hypothalamic gene expression [messenger RNA (mRNA)] of two appetite stimulating neuropeptides, neuropeptide Y (NPY) and galanin (GAL) in lean (+/+) and genetically obese (fa/fa) Zucker rats at 11, 24 and 40 weeks of age and their responsiveness to food deprivation. At 11 weeks of age, hypothalamic NPY mRNA levels of fa/fa rats were similar to those observed in lean littermates. However, NPY mRNA levels of fa/fa rats were significantly greater than those of lean rats at 24 (+126%; P < 0.01) and 40 (+65%; P < 0.05) weeks of age. Food deprivation caused a significant increase in NPY mRNA levels in both lean and fa/fa Zucker rats at 11 and 24 weeks of age, but not at 40 weeks old rats. Hypothalamic GAL mRNA showed a different pattern of change. The relative content of GAL mRNA in 11 week old obese rats was significantly lower (-68%; P < 0.05) than that of lean rats, while GAL and mRNA was significantly higher in 40 week old (+57%; P < 0.05) obese rats compared to their lean littermates. At 24 weeks of age, hypothalamic GAL mRNA levels did not differ between lean and obese rats. Food deprivation induced no change in hypothalamic GAL mRNA in lean rats of all 3 ages; however, it caused an increase of GAL mRNA in obese rats at 11 (+60%; P < 0.05) and 24 (+44%; P < 0.05) weeks, but not at 40 weeks. These findings demonstrate that hypothalamic NPY and GAL gene expression differs between lean and obese rats, as a function of age and nutritional state and they also suggest that alterations in NPY and GAL mRNA levels of the obese rat are secondary manifestations of the obese state, rather than the primary cause of obesity.

Original languageEnglish (US)
Pages (from-to)195-202
Number of pages8
JournalMolecular Brain Research
Volume19
Issue number3
DOIs
StatePublished - 1993
Externally publishedYes

Fingerprint

Zucker Rats
Galanin
Neuropeptide Y
Gene Expression
Messenger RNA
Food Deprivation
Appetite
Neuropeptides
Northern Blotting

Keywords

  • Aging
  • Food deprivation
  • Galanin mRNA
  • Hypothalamus
  • Lean Zucker rat
  • Neuropeptide Y
  • Obese Zucker rat

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience

Cite this

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title = "Critical effects of aging and nutritional state on hypothalamic neuropeptide Y and galanin gene expression in lean and genetically obese Zucker rats",
abstract = "We have investigated, by Northern blot analysis, the hypothalamic gene expression [messenger RNA (mRNA)] of two appetite stimulating neuropeptides, neuropeptide Y (NPY) and galanin (GAL) in lean (+/+) and genetically obese (fa/fa) Zucker rats at 11, 24 and 40 weeks of age and their responsiveness to food deprivation. At 11 weeks of age, hypothalamic NPY mRNA levels of fa/fa rats were similar to those observed in lean littermates. However, NPY mRNA levels of fa/fa rats were significantly greater than those of lean rats at 24 (+126{\%}; P < 0.01) and 40 (+65{\%}; P < 0.05) weeks of age. Food deprivation caused a significant increase in NPY mRNA levels in both lean and fa/fa Zucker rats at 11 and 24 weeks of age, but not at 40 weeks old rats. Hypothalamic GAL mRNA showed a different pattern of change. The relative content of GAL mRNA in 11 week old obese rats was significantly lower (-68{\%}; P < 0.05) than that of lean rats, while GAL and mRNA was significantly higher in 40 week old (+57{\%}; P < 0.05) obese rats compared to their lean littermates. At 24 weeks of age, hypothalamic GAL mRNA levels did not differ between lean and obese rats. Food deprivation induced no change in hypothalamic GAL mRNA in lean rats of all 3 ages; however, it caused an increase of GAL mRNA in obese rats at 11 (+60{\%}; P < 0.05) and 24 (+44{\%}; P < 0.05) weeks, but not at 40 weeks. These findings demonstrate that hypothalamic NPY and GAL gene expression differs between lean and obese rats, as a function of age and nutritional state and they also suggest that alterations in NPY and GAL mRNA levels of the obese rat are secondary manifestations of the obese state, rather than the primary cause of obesity.",
keywords = "Aging, Food deprivation, Galanin mRNA, Hypothalamus, Lean Zucker rat, Neuropeptide Y, Obese Zucker rat",
author = "Meena Jhanwar-Uniyal and {Chua, Jr.}, {Streamson C.}",
year = "1993",
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T1 - Critical effects of aging and nutritional state on hypothalamic neuropeptide Y and galanin gene expression in lean and genetically obese Zucker rats

AU - Jhanwar-Uniyal, Meena

AU - Chua, Jr., Streamson C.

PY - 1993

Y1 - 1993

N2 - We have investigated, by Northern blot analysis, the hypothalamic gene expression [messenger RNA (mRNA)] of two appetite stimulating neuropeptides, neuropeptide Y (NPY) and galanin (GAL) in lean (+/+) and genetically obese (fa/fa) Zucker rats at 11, 24 and 40 weeks of age and their responsiveness to food deprivation. At 11 weeks of age, hypothalamic NPY mRNA levels of fa/fa rats were similar to those observed in lean littermates. However, NPY mRNA levels of fa/fa rats were significantly greater than those of lean rats at 24 (+126%; P < 0.01) and 40 (+65%; P < 0.05) weeks of age. Food deprivation caused a significant increase in NPY mRNA levels in both lean and fa/fa Zucker rats at 11 and 24 weeks of age, but not at 40 weeks old rats. Hypothalamic GAL mRNA showed a different pattern of change. The relative content of GAL mRNA in 11 week old obese rats was significantly lower (-68%; P < 0.05) than that of lean rats, while GAL and mRNA was significantly higher in 40 week old (+57%; P < 0.05) obese rats compared to their lean littermates. At 24 weeks of age, hypothalamic GAL mRNA levels did not differ between lean and obese rats. Food deprivation induced no change in hypothalamic GAL mRNA in lean rats of all 3 ages; however, it caused an increase of GAL mRNA in obese rats at 11 (+60%; P < 0.05) and 24 (+44%; P < 0.05) weeks, but not at 40 weeks. These findings demonstrate that hypothalamic NPY and GAL gene expression differs between lean and obese rats, as a function of age and nutritional state and they also suggest that alterations in NPY and GAL mRNA levels of the obese rat are secondary manifestations of the obese state, rather than the primary cause of obesity.

AB - We have investigated, by Northern blot analysis, the hypothalamic gene expression [messenger RNA (mRNA)] of two appetite stimulating neuropeptides, neuropeptide Y (NPY) and galanin (GAL) in lean (+/+) and genetically obese (fa/fa) Zucker rats at 11, 24 and 40 weeks of age and their responsiveness to food deprivation. At 11 weeks of age, hypothalamic NPY mRNA levels of fa/fa rats were similar to those observed in lean littermates. However, NPY mRNA levels of fa/fa rats were significantly greater than those of lean rats at 24 (+126%; P < 0.01) and 40 (+65%; P < 0.05) weeks of age. Food deprivation caused a significant increase in NPY mRNA levels in both lean and fa/fa Zucker rats at 11 and 24 weeks of age, but not at 40 weeks old rats. Hypothalamic GAL mRNA showed a different pattern of change. The relative content of GAL mRNA in 11 week old obese rats was significantly lower (-68%; P < 0.05) than that of lean rats, while GAL and mRNA was significantly higher in 40 week old (+57%; P < 0.05) obese rats compared to their lean littermates. At 24 weeks of age, hypothalamic GAL mRNA levels did not differ between lean and obese rats. Food deprivation induced no change in hypothalamic GAL mRNA in lean rats of all 3 ages; however, it caused an increase of GAL mRNA in obese rats at 11 (+60%; P < 0.05) and 24 (+44%; P < 0.05) weeks, but not at 40 weeks. These findings demonstrate that hypothalamic NPY and GAL gene expression differs between lean and obese rats, as a function of age and nutritional state and they also suggest that alterations in NPY and GAL mRNA levels of the obese rat are secondary manifestations of the obese state, rather than the primary cause of obesity.

KW - Aging

KW - Food deprivation

KW - Galanin mRNA

KW - Hypothalamus

KW - Lean Zucker rat

KW - Neuropeptide Y

KW - Obese Zucker rat

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