Positive and Negative Feedback Control by Estrogen of Luteinizing Hormone Secretion in the Rhesus Monkey12

Karsch, Fred J.; Dierschke, Donald J.; Weick, Richard F.; Yamaji, Taiki; Hotchkiss, J.; Knobil, E.

doi:10.1210/endo-92-3-799

Cited by 302 publications

(143 citation statements)

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“…Because the permeability, diameter, wall thickness, and concentration gradient are constant in the capsule, the length of the capsule determines the diffusion rate (Legan et al, 1975). Estradiol capsules of this size provide constant circulating levels of approximately 75 pg/ml estradiol for over one year (Legan et al, 1975;Karsch et al, 1973). Purified hCG (Prospec-Tany) was reconstituted in deionized water (400 IU/ml) and stored in aliquots at −20°C for 1-4 weeks.…”

Section: Hormonesmentioning

confidence: 99%

Human chorionic gonadotropin (a luteinizing hormone homologue) decreases spatial memory and increases brain amyloid-β levels in female rats

Berry

Tomidokoro

Ghiso

et al. 2008

Hormones and Behavior

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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 Etreated female rats. In the Object Location Memory Task, ovariectomized (ovxed) rats treated with E and either a single high dose (400IU/kg) or a lower repeated dose of hCG (75 IU/kg hourly for 8 hours) 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 (400IU/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.

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Section: Hormonesmentioning

confidence: 99%

Human chorionic gonadotropin (a luteinizing hormone homologue) decreases spatial memory and increases brain amyloid-β levels in female rats

Berry

Tomidokoro

Ghiso

et al. 2008

Hormones and Behavior

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show abstract

“…Silastic capsules were prepared according to the method of Karsch et aJ. 17 and Legan et al 18 Maximum sex skin turgescence occurred during 7 to 8 days after capsule insertion, and deturgescence was complete 8 to 9 days after capsule removal. Two cycles of capsule insertion and removal were accomplished in a total of nine animals.…”

Section: Animalsmentioning

confidence: 99%

Estradiol-17 beta affects estrogen receptor distribution and elevates progesterone receptor content in baboon aorta.

Lin¹,

González²,

Carey³

et al. 1986

Arteriosclerosis

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“…Webster & Haresign (1983) of Webster & Haresign (1983). Immediately before ovariectomy, 9 ewes of each breed had been given a subcutaneous oestradiol implant, of a type designed to maintain plasma oestradiol levels of 3-5 pg/ml (Karsch et al, 1973 Haresign & Lamming (1982a) to increase the sensitivity of the assay to 0-3 ng equiv. NIH-LH-S17/ml plasma.…”

Section: Introductionmentioning

confidence: 99%

Evidence that the onset of seasonal anoestrus in the ewe may be independent of increasing prolactin concentrations and daylength

Worthy¹,

Haresign²

1983

Reproduction

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Positive and Negative Feedback Control by Estrogen of Luteinizing Hormone Secretion in the Rhesus Monkey12

Cited by 302 publications

References 0 publications

Human chorionic gonadotropin (a luteinizing hormone homologue) decreases spatial memory and increases brain amyloid-β levels in female rats

Human chorionic gonadotropin (a luteinizing hormone homologue) decreases spatial memory and increases brain amyloid-β levels in female rats

Estradiol-17 beta affects estrogen receptor distribution and elevates progesterone receptor content in baboon aorta.

Evidence that the onset of seasonal anoestrus in the ewe may be independent of increasing prolactin concentrations and daylength

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