22045
Estrogen exerts its action through two distinct estrogen receptors ( ERs ) either ER - alpha or ER - beta .
 Chemical: Estrogen; Chemical: estrogen
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Estrogen; Chemical: estrogen