2277
Many studies have pointed out the possibility of " masked " organic factors in erectile impotence , detectable only by means of laboratory investigations : mild hypogonadism , hyperprolactinemia , occlusions selectively located at the site of the sexual arteries , venous incompetence , subclinical neuropathies .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 None