28781
Among antioxidant defences , catalase and glutathione peroxidases did not exhibit variations in enzymatic activity , while the corresponding gene transcriptions were up - and down - regulated , respectively ; unchanged mRNA levels of superoxide dismutase confirmed the non - synchronous pathways of variations for such antioxidants .
 glutathione, superoxide
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 glutathione, superoxide