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Next , we examined expression of genes encoding five progesterone metabolizing enzymes : the 3 - keto and 20 - ketosteroid reductases ( AKR1C1 - AKR1C3 ) and 5 alpha - reductases ( SRD5A1 and SRD5A2 ) ; and the opposing 20 alpha - hydroxysteroid dehydrogenase ( HSD17B2 ) .
 Chemical: progesterone; Chemical: 3 - keto and 20 - ketosteroid; Chemical: 20 alpha - hydroxysteroid
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: progesterone; Chemical: 3 - keto and 20 - ketosteroid; Chemical: 20 alpha - hydroxysteroid