18317
Interestingly , gene expression results further showed that exendin - 4 not only inhibited bone resorption by increasing OPG / RANKL ratio , but also promoted bone formation by increasing the expressions of OC , Col1 , Runx2 , and ALP , which exhibited dual regulatory effects on bone turnover as compared with previous anti - osteoporotic agents .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None