23035
A mechanism for thyroid - dependent control of seasonality has been proposed , in which exposure to long day lengths induces rapid local conversion of T4 to its bioactive form , T3 , via the up - regulation of the enzyme type 2 iodothyronine deiodinase ( Dio2 ) in the brain , and the down - regulation of Dio3 ( which inactivates T3 ) .
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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:
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