8990
This method was successfully extended to human retinoic X receptor alpha , glucocorticoid receptor , and progesterone receptor , thus providing a basis for a new, faster assay to determine simultaneously the affinity and conformation of receptors when bound to a given ligand.
 human retinoic X receptor alpha, glucocorticoid receptor, progesterone receptor
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:
 human retinoic X receptor alpha, glucocorticoid receptor, progesterone receptor