1863
Treatment with FGF21 maintained the normal nocturnal increase in oxygen consumption and carbon dioxide production into the early light phase in hamsters in LD , indicating increased energy expenditure , although locomotor activity was unaffected .
 oxygen, carbon dioxide
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 oxygen, carbon dioxide