5798
Vasopressin ( AVP ) , the antidiuretic hormone , is a cyclic nonapeptide that acts through binding to G protein - coupled specific membrane receptors pharmacologically divided into three subtypes ( V1a , V1b , and V2 ) linked to distinct second messengers .
 Vasopressin, AVP, G protein - coupled specific membrane receptors, V1a, V1b, V2
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 Vasopressin, AVP, G protein - coupled specific membrane receptors, V1a, V1b, V2