9893
Hyperplasia further progressed in the livers of Kcnk1 ( - / - ) male mice compared with those of Kcnk1 ( + / + ) males after phenobarbital treatment .
 Chemical: phenobarbital
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: phenobarbital