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To investigate this , we measured changes in gene expression the dorsal striatum , where 17 beta - estradiol modulates catecholamine signaling .
 17 beta - estradiol, catecholamine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 17 beta - estradiol, catecholamine