16729
Three variables of cardiac vagal effects ( the root mean square of successive differences [ rMSSD ] in the interbeat interval of the heart rate [ IBI ] , heart - rate variability [ HRV ] caused by peak - valley respiratory sinus arrhythmia [ pvRSA ] , and high - frequency power [ HF ] ) and heart rate ( HR ) were obtained at seven time points during the clamps , characterised by increasing levels of insulin ( achieved by administering insulin plus glucose , glucose only , glucose and GLP - 1 , and glucose and GLP - 1 combined with arginine ) .
 glucose, glucose, glucose, glucose, arginine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 glucose, glucose, glucose, glucose, arginine