1491
The renin - angiotensin system is activated in both obstructive nephropathy and PKD , which may contribute to tubular atrophy and interstitial fibrosis , which characterize the progression of both conditions .
 tubular, interstitial
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 tubular, interstitial