867
The present study investigated whether impacting early in development the hypothalamic - pituitary - adrenal axis , by exposing Mecp2 - 308 mutant pups to a low dose of corticosterone ( 50 micro g / ml , during the 1st week of life ) may contrast RTT - related abnormalities in neuroendocrine regulation and behavioural adaptation at adulthood .
 corticosterone
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 corticosterone