12122
Treatment with two different schedules of oral calcitriol (five patients with 0.5 microgram/day for 1 month and four patients with 2 micrograms/day for 7 days) did not change VDR concentrations .
 VDR
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 VDR