2370
The binding sites fulfil the required criteria for specific steroid binding sites however differ somewhat from the classic androgen receptors from genital skin fibroblast : in fertile adult males (n = 20) the binding sites showed (1) a high affinity for testosterone (1.32 +/- 0.49 nM; mean +/- SD), (2) a saturable capacity (184 +/- 52 binding sites per cell; mean +/- SD), and (3) a characteristic competitive binding profile for other steroid hormones (relative binding affinities: testosterone = dihydrotestosterone > 17 beta-estradiol > progesterone , whereas aldosterone, 17-hydroxy-progesterone and cortisol did not compete appreciably).
 binding sites, steroid binding sites, binding sites, genital skin fibroblast, binding sites, androgen receptors
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:
 binding sites, steroid binding sites, binding sites, genital skin fibroblast, binding sites, androgen receptors