6848
Cells exposed to alpha - MeDA showed an increase in intracellular glutathione ( GSH ) levels , which , at the 48 h time - point , was not dependent in the activity increase of gamma - glutamylcysteine synthetase ( gamma - GCS ) , revealing a possible transient effect .
 alpha - MeDA, glutathione, GSH, gamma - glutamylcysteine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 alpha - MeDA, glutathione, GSH, gamma - glutamylcysteine