Human chorionic gonadotropin (a Luteinizing Hormone homologue) decreases spatial memory and increases brain amyloid-ß levels in female rats

Title:
Human chorionic gonadotropin (a Luteinizing Hormone homologue) decreases spatial memory and increases brain amyloid-ß levels in female rats
Authors:
Berry, Anne; Tomidokoro, Yasushi; Ghiso, Jorge; Thornton, Janice E.
Abstract:
Numerous studies have suggested that estradiol (E) improves spatial memory as female rats with E perform better than those without E. However there is an inverse relationship between E and luteinizing hormone (LH) levels and LH could play a role. We examined whether treatment with the LH homologue human chorionic gonadotropin (hCG), would impair spatial memory of adult E-treated female rats. In the object location memory task, ovariectomized (ovxed) rats treated with E and either a single high dose (400 IU/kg) or a lower repeated dose of hCG (75 IU/kg hourly for 8 h) showed spatial memory disruption compared to ovxed rats treated with estradiol alone. Impairment was attributed to memory disruption as performance improved with shortened delay between task exposure and testing. Tests on another spatial memory task, the Barnes maze, confirmed that hCG (400 IU/kg) can impair memory: although E + veh treated animals made significantly fewer hole errors across time, E + hCG-treated did not. In humans, high LH levels have been correlated with Alzheimer's disease (AD). Because brain amyloid-beta (Aβ) species have been implicated as a toxic factor thought to cause memory loss in AD, we analyzed whether hCG-treated animals had increased Aβ levels. Levels of Aβ from whole brains or hippocampi were assessed by Western blot. hCG treatment to E-implanted females significantly increased soluble Aβ40 and Aβ42 levels. These results indicate that high levels of LH/hCG can impair spatial memory, and an increase in brain Aβ species may account for the memory impairment in hCG-treated rats.
Citation:
Berry, A., Y. Tomidokoro, J. Ghiso, and J. E. Thorton. 2008. "Human chorionic gonadotropin (a Luteinizing Hormone homologue) decreases spatial memory and increases brain amyloid-ß levels in female rats." Hormones And Behavior 54(1): 143-152.
Publisher:
Elsevier for Academic Press
DATE ISSUED:
2008
Department:
Neuroscience
Type:
article
PUBLISHED VERSION:
10.1016/j.yhbeh.2008.02.006
PERMANENT LINK:
http://hdl.handle.net/11282/310459

Full metadata record

DC FieldValue Language
dc.contributor.authorBerry, Anneen_US
dc.contributor.authorTomidokoro, Yasushien_US
dc.contributor.authorGhiso, Jorgeen_US
dc.contributor.authorThornton, Janice E.en_US
dc.date.accessioned2013-12-23T16:33:35Z-
dc.date.available2013-12-23T16:33:35Z-
dc.date.issued2008en
dc.identifier.citationBerry, A., Y. Tomidokoro, J. Ghiso, and J. E. Thorton. 2008. "Human chorionic gonadotropin (a Luteinizing Hormone homologue) decreases spatial memory and increases brain amyloid-ß levels in female rats." Hormones And Behavior 54(1): 143-152.en_US
dc.identifier.issn0018-506Xen_US
dc.identifier.urihttp://hdl.handle.net/11282/310459-
dc.description.abstractNumerous studies have suggested that estradiol (E) improves spatial memory as female rats with E perform better than those without E. However there is an inverse relationship between E and luteinizing hormone (LH) levels and LH could play a role. We examined whether treatment with the LH homologue human chorionic gonadotropin (hCG), would impair spatial memory of adult E-treated female rats. In the object location memory task, ovariectomized (ovxed) rats treated with E and either a single high dose (400 IU/kg) or a lower repeated dose of hCG (75 IU/kg hourly for 8 h) showed spatial memory disruption compared to ovxed rats treated with estradiol alone. Impairment was attributed to memory disruption as performance improved with shortened delay between task exposure and testing. Tests on another spatial memory task, the Barnes maze, confirmed that hCG (400 IU/kg) can impair memory: although E + veh treated animals made significantly fewer hole errors across time, E + hCG-treated did not. In humans, high LH levels have been correlated with Alzheimer's disease (AD). Because brain amyloid-beta (Aβ) species have been implicated as a toxic factor thought to cause memory loss in AD, we analyzed whether hCG-treated animals had increased Aβ levels. Levels of Aβ from whole brains or hippocampi were assessed by Western blot. hCG treatment to E-implanted females significantly increased soluble Aβ40 and Aβ42 levels. These results indicate that high levels of LH/hCG can impair spatial memory, and an increase in brain Aβ species may account for the memory impairment in hCG-treated rats.en_US
dc.publisherElsevier for Academic Pressen_US
dc.identifier.doi10.1016/j.yhbeh.2008.02.006-
dc.subject.departmentNeuroscienceen_US
dc.titleHuman chorionic gonadotropin (a Luteinizing Hormone homologue) decreases spatial memory and increases brain amyloid-ß levels in female ratsen_US
dc.typearticleen_US
dc.identifier.journalHormones And Behavioren_US
dc.identifier.volume54en_US
dc.identifier.issue1en_US
dc.identifier.startpage143en_US
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