1442
The objective of this study was to comprehensively characterize the effects of estrogen and progesterone on the expression and activity of major drug - metabolizing P450s .
 Chemical: estrogen; Chemical: progesterone
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: progesterone