TY - JOUR
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, Streamson C.
N1 - Funding Information:
Acknowledgements. This work is supported by NIH Obesity Core Center Grant 5P30AM26687. We are grateful to Dr. Sarah F. Leibowitz for her continuing support and encouragement in preparation of this manuscript.
PY - 1993/8
Y1 - 1993/8
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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U2 - 10.1016/0169-328X(93)90026-L
DO - 10.1016/0169-328X(93)90026-L
M3 - Article
C2 - 7692207
AN - SCOPUS:0027214505
SN - 0169-328X
VL - 19
SP - 195
EP - 202
JO - Molecular Brain Research
JF - Molecular Brain Research
IS - 3
ER -