530
There was a more marked rise of the number of receptors in middle-aged (44-55 years) hypertensives vs elderly (61-80 years) subjects after captopril treatment .
 protein: receptors
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 protein: receptors