18114
The methods detailed here utilize an entirely different methodology , reverse - transcription quantitative polymerase chain reaction , to determine the relative expression levels of 4 genes after exposure to either 17 beta - estradiol or 17 beta - trenbolone and , by extension , the effects of EDCs on the phenotypic status of the gonad .
 17 beta - estradiol, 17 beta - trenbolone
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 17 beta - estradiol, 17 beta - trenbolone