Ovarian hormones and cognition in the aged female rat: II. progesterone supplementation reverses the cognitive enhancing effects of ovariectomy.
The authors hypothesized that the progesterone component of some hormone replacement therapies in women is detrimental to cognition. A previous study showed that ovariectomy (ovx) in aged rats enhanced spatial working memory and decreased elevated progesterone levels. The current study evaluated whether progesterone administration counteracts these cognitive enhancing effects of ovx. Aged sham and aged ovx rats given progesterone exhibited compromised learning of the working and reference memory components of the task, and made more working memory errors on the latter testing days compared with aged ovx rats not given progesterone. Results suggest that whereas ovx of the aged female rat enhances learning and the ability to handle numerous items of spatial working memory information, progesterone is detrimental to these aspects of performance. These findings may speak to studies in menopausal women which suggest that combination hormone therapies have a negative impact on cognition.
Department of Physiology and Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA. bimonte@musc.edu
Heather A
HA
Bimonte-Nelson
Rachel S
RS
Singleton
Brice J
BJ
Williams
Ann-Charlotte E
AC
Granholm
D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal; D003071:Cognition / Q000187:drug effects*; D005260:Female; D042341:Gonadal Hormones / Q000502:physiology*; D018782:Maze Learning / Q000187:drug effects; D008570:Memory, Short-Term / Q000187:drug effects*; D010052:Ovariectomy / Q000379:methods*; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D013037:Spatial Behavior / Q000187:drug effects
D042341:Gonadal Hormones; D011374:Progesterone