16148
TTX content ( mu g / g ) in each tissue , determined by liquid chromatography / mass spectrometry , revealed that the TTX distribution profile , particularly the TTX content of the liver , greatly differed between the two ages ; the TTX score of 15 - month old fish ( 3 . 3 mu g / g ) was nearly 5 - fold that of 6 - month old fish ( 0 . 68 mu g / g ) .
 TTX, TTX, TTX, TTX
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 TTX, TTX, TTX, TTX