The effects of androgens on cognitive, morphological, and neurochemical functions in female rats.
Item
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Title
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The effects of androgens on cognitive, morphological, and neurochemical functions in female rats.
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Identifier
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AAI3325460
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identifier
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3325460
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Creator
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Mohan, Govini.
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Contributor
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Adviser: Victoria Luine
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Date
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2008
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Neuroscience | Psychology, Psychobiology
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Abstract
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Estrogen replacement therapy promotes memory function, but is associated with harmful side effects in women. Androgens minimize some of these side effects and enhance cognitive function in males and females, but results remain equivocal. The focus of this research is to determine whether androgens affect cognition of female rats.;Subchronic (two day injections) and acute (single injection) treatment with the androgens, dehydroepiandrosterone (DHEA), testosterone propionate (TP), dihydrotestosterone (DHT), and androstenedione (AD) were used in ovariectomized rats to assess effects on object placement (spatial) and object recognition (nonspatial) memory. Androgens differentially affected these tasks, with enhanced spatial memory by subchronic treatment with DHEA, DHT, and AD, and enhanced nonspatial memory with TP. Acute treatment with DHEA and AD, but not DHT enhanced spatial memory and acute TP enhanced nonspatial memory. DHEA and TP's enhancing effects on memory were not blocked by the aromatase inhibitor, letrozole, suggesting that these effects were mediated by androgens, and not via conversion of androgens to estrogen. DHEA, TP, DHT and AD did not influence anxiety levels on the elevated plus maze suggesting that memory enhancements were due to effects on mnemonic processes. Golgi impregnation and analyses found that treatment with DHEA and TP increased apical and basal dendritic spine density of the prefrontal cortex, and only basal spine density of CA1 of the hippocampus, brain areas known to be involved in memory. Neurochemical analyses using high performance liquid chromatography (HPLC) found that treatment with DHEA, TP and estradiol benzoate (EB) altered norepinephrine, serotonergic, and dopaminergic activities in the prefrontal cortex, CA1, CA3, and dentate gyrus of the hippocampus, striatum, and vertical diagonal band. Subchronic treatment with DHT and AD altered mainly norepinephrine activity in the above mentioned brain areas.;In summary, the current findings provide novel behavioral, physiological, morphological, and neurochemical information about the cognitive role of androgens in female ovariectomized rats. Results show that androgens enhance memory through activational effects, and changes in dendritic spine density and brain monoaminergic activity may be important in mediating these effects. Furthermore, these androgens may have a potential role as hormone replacement therapy in postmenopausal women.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
