Conjugated equine estrogen enhances rats' cognitive, anxiety, and social behavior

The ovarian hormone, 17beta-estradiol (E2), has numerous targets in the body and brain, and can influence cognitive, affective, and social behavior. However, functional effects of commonly prescribed E2-based hormone therapies are less known. The effects of conjugated equine estrogen (CEE) on middle-aged female rats for cognitive (object recognition), anxiety (open field, plus maze), and social (social interaction, lordosis) behavior were compared with vehicle. Our hypothesis that CEE would enhance cognitive, anxiety, and social behavior was supported. CEE improved object recognition, increased time spent on the open arms of the plus maze, and time spent interacting with a conspecific, but did not alter open field behavior or lordosis. Thus, CEE can enhance cognitive, antianxiety, and social behavior of middle-aged rats.