Acute progesterone treatment impairs spatial working memory in intact male and female rats.
BACKGROUND
The aim of this study was to determine if progesterone affects spatial and non-spatial working memory in intact male and female rats.


METHODS
Rats received subcutaneous injections of progesterone (500 microg) or vehicle (sesame oil). Four hours after hormone treatments, spatial and non-spatial memories were tested using novel object recognition and spatial object recognition tasks.


RESULTS
Vehicle-treated female rats had higher progesterone serum levels than males, but progesterone treatment produced equivalent progesterone serum levels in both sexes. In the object recognition task--a non-spatial memory task-females showed better performance than males, and progesterone had no effect on either sex. However, in the object replacement task--a spatial memory task-progesterone significantly impaired the retention in both male and female rats as compared with vehicle-treated groups.


CONCLUSIONS
These results suggest that acute progesterone treatment interferes with spatial working memory consolidation, but not recognition (non-spatial) working memory. As such, the observed sexual incongruities in progesterone's effects on working memory suggest that progesterone-based hormone therapies have a negative impact on cognition.
Department of Psychology, Hunter College of the City University of New York, 10065, USA.
Wei-Lun
WL
Sun
Victoria N
VN
Luine
Luyi
L
Zhou
Hui-Bing
HB
Wu
Karen M
KM
Weierstall
Shirzad
S
Jenab
Vanya
V
Quiñiones-Jenab
D000818:Animals; D003071:Cognition / Q000187:drug effects; D015914:Estrogen Replacement Therapy; D005260:Female; D008297:Male; D008568:Memory / Q000187:drug effects*; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D012715:Sesame Oil / Q000494:pharmacology
D011374:Progesterone; D012715:Sesame Oil