13471
In contrast , stressed mice lacking ghrelin receptors ( GHSR KO mice ) or C57BL mice receiving chronic intracerebroventricular delivery of the ghrelin receptor antagonist [ d - Lys ( 3 ) ] - GHRP - 6 show attenuated weight gain and feeding responses under the same social stress paradigm .
 Chemical: Lys
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Lys