6563
Rats fed ad lib . on 45 % or 60 % fat diet were heavier and fatter than controls , and had reduced neuropeptide Y ( NPY ) gene expression in the ARC .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None