4626
The aim of the present study was to investigate the involvement of estrogen receptors in the activation of phospholipase C ( PLC ) - phosphoinositide hydrolysis in the hippocampus from rats in estrous and proestrous phases .
 Chemical: estrogen
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: estrogen 
Answer:
 Chemical: estrogen