Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 144-155).

Thesis (M.Eng.). / Written for the Dept. of Chemical Engineering. Title from title page of PDF (viewed 2008/01/14). Includes bibliographical references.

Thesis (M.S.)--Baylor University, 2005. / Includes bibliographical references (p. 61-68).

abstract: Ethinyl estradiol, (EE) a synthetic, orally bio-available estrogen, is the most commonly prescribed form of estrogen in oral contraceptives (Shively, C., 1998), and is found in at least 30 different contraceptive formulations currently prescribed to women (Curtis et al., 2005). EE is also used in hormone therapies prescribed to menopausal women, such as FemhrtTM (Simon et al., 2003). Thus, EE is prescribed clinically to women at ages ranging from puberty through reproductive senescence. Here, in two separate studies, the cognitive effects of cyclic or tonic EE administration following ovariectomy (Ovx) were evaluated in young, female rats. Study I assessed the cognitive effects of low and high doses of EE, delivered tonically via a subcutaneous osmotic pump. Study II evaluated the cognitive effects of low, medium, and high doses of EE administered via a daily subcutaneous injection. For these studies, the low and medium doses correspond to the range of doses currently used in clinical formulations, and the high dose corresponds to the range of doses prescribed to a generation of women between 1960 and 1970, when oral contraceptives first became available. For each study, cognition was evaluated with a battery of maze tasks tapping several domains of spatial learning and memory. At the highest dose, EE treatment impaired multiple domains of spatial memory relative to vehicle treatment, regardless of administration method. When given cyclically at the low and medium doses, EE did not impact working memory, but transiently impaired reference memory during the learning phase of testing. Of the doses and regimens tested here, only EE at the highest dose impaired several domains of memory; this was seen for both cyclic and tonic regimens. Cyclic and tonic delivery of low EE, a dose that corresponds to doses used in the clinic today, resulted in transient and null impairments, respectively, on cognition. / Dissertation/Thesis / M.A. Psychology 2012

Submitted by Fabíola Silva (fabiola.silva@famerp.br) on 2016-06-22T19:13:02Z No. of bitstreams: 1 luizrobertofalleirosjunior_dissert.pdf: 2855726 bytes, checksum: 19672bd7d4c60e301a52bec076ff8240 (MD5) / Made available in DSpace on 2016-06-22T19:13:02Z (GMT). No. of bitstreams: 1 luizrobertofalleirosjunior_dissert.pdf: 2855726 bytes, checksum: 19672bd7d4c60e301a52bec076ff8240 (MD5) Previous issue date: 2015-09-28 / Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP / The prostate is an accessory gland of genital system responsible for producing an alkaline liquid which ensures sperm survival and capacitation. Its development occurs under the influence of an androgen and estrogen regulated and precise control, so sensible interferences may predispose this gland to developing diseases such as benign prostatic hyperplasia and cancer during adult and senile life. Inappropriate exposure to exogenous estrogens in embryonic and neonatal development period has been related to permanent disturbances in morphophysiology of various organs of the male reproductive system. Epidemiological studies indicate that men who were exposed to estrogenic compounds during intrauterine and neonatal development had higher probability of infertility and testicular and prostate cancer. Until now, it is not possible to say whether there are intrinsic factors of development that may predispose prostatic gland to the development of cancer with age. However, as early exposure to steroid hormones can permanently alter various reproductive organs, it is questionable whether such agents may interfere in the prostate structure and physiology. Based on these reports, the aim of this study was to analyze morphologically the ventral prostate of adult gerbils exposed to ethynylestradiol (EE) during the first week of prenatal development. To this, we employed morphological, stereological-morphometrical, immunohistochemical and ultrastructural methods. The results showed that the postnatal exposure to EE duplicated the prostatic complex weight, increasing the relative frequency of epithelial and stromal compartments, besides the secretory activity of the ventral lobe of the prostate. All glands exposed to EE showed strong stromal reshuffling and some foci of epithelial hyperplasia and inflammatory infiltrated in both luminal and epithelial or stromal compartments. Cells positive for AR and PCNA increased into the epithelial and stromal tissues. ERα-positive cells, which are normally found into stromal compartment of intact prostates, were frequently observed in the prostatic epithelial of treated animals. This study demonstrated that the exposure to EE during the postnatal development causes histophysiological alterations of this gland, predisposing to the development of prostatic lesions during life. These results are important taking account public health, considering the EE has been largely used by women worldwide. Moreover, the bioaccumulation of this chemical has been increased in different ecosystems. / A próstata é uma glândula acessória do sistema genital responsável pela produção de um líquido alcalino que garante a capacitação e sobrevivência dos espermatozóides. O seu desenvolvimento ocorre sob influência de um controle androgênico e estrogênico regulado e preciso, de forma que sensíveis interferências podem predispor esta glândula a desenvolver doenças como hiperplasia prostática benigna e câncer durante a vida adulta e senil. A exposição inapropriada a estrógenos exógenos no período de desenvolvimento embrionário e neonatal tem sido relacionada a distúrbios permanentes na morfofisiologia de vários órgãos do sistema reprodutor masculino. Estudos epidemiológicos indicam que homens que foram expostos a componentes estrogênicos durante o desenvolvimento intra-uterino e neonatal apresentaram maior probabilidade de ocorrência de infertilidade e de câncer de testículo e próstata. Até o momento, não é possível afirmar se existem fatores intrínsecos do desenvolvimento que podem predispor a glândula prostática ao desenvolvimento de câncer com a idade. Porém, como a exposição precoce a hormônios esteróides é capaz de alterar permanentemente vários órgãos reprodutivos, torna-se questionável se esses agentes também podem interferir na estrutura e fisiologia prostática. Com base nesses relatos, o objetivo deste estudo foi analisar morfologicamente a próstata ventral de gerbilos adultos expostos ao ethynylestradiol (EE) durante a primeira semana de desenvolvimento pós-natal. Para isso, foram empregados métodos morfológicos, morfométricos-estereológicos, imunohistoquímicos e ultraestruturais. Os resultados obtidos demonstraram que a exposição pós-natal ao EE duplicou o peso do complexo prostático, aumentando a frequência relativa dos compartimentos epitelial e estromal e a atividade secretora no lobo ventral da próstata. Todas as glândulas expostas ao EE apresentaram intensa remodelação estromal, focos de hiperplasia epitelial e de infiltrados inflamatórios intersticiais e intraluminais. Células AR e PCNA-positivas tornaram-se significativamente mais frequentes no epitélio e no estroma. Células ERα-positivas, que foram restritas ao compartimento estromal em próstatas controle, foram frequentemente observadas no epitélio prostático dos animais tratados. O presente estudo demonstrou que a exposição ao EE durante o desenvolvimento pós-natal da próstata ventral pode causar alterações organizacionais na histofisiologia deste órgão, predispondo os indivíduos precocemente a lesões prostáticas. Estes resultados são de grande importância para a saúde pública, visto que o EE tem sido cada vez mais utilizado por mulheres em todo o mundo, e que a bioacumulação deste químico ambiental tem atingido níveis cada vez mais altos nos diferentes ecossistemas.

Orientador: Sebastião RobertoTaboga / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T22:39:47Z (GMT). No. of bitstreams: 1 Perez_AnaPauladaSilva_M.pdf: 6001319 bytes, checksum: e128a337509c2f2d797523dafdca8524 (MD5) Previous issue date: 2010 / Resumo: Nos machos, a morfogênese prostática é um evento comandado por andrógenos, que agem diretamente via fatores parácrinos secretados pelo mesênquima. Nas fêmeas, o desenvolvimento embriológico da próstata parece ocorrer em níveis baixos de hormônios esteróides, porém a presença desses hormônios no organismo adulto induz a diferenciação e atividade secretória das células prostáticas. A exposição precoce a estrógeno no período de desenvolvimento embrionário e neonatal tem sido relacionada a distúrbios permanentes na morfofisiologia de vários órgãos do sistema reprodutor de ambos os sexos. Estudos epidemiológicos indicam que homens expostos a componentes estrogênicos durante o desenvolvimento intra-uterino apresentam maior probabilidade de serem inférteis e de desenvolverem câncer de testículo e próstata, enquanto as mulheres tornam-se mais susceptíveis a desenvolver câncer de mama, útero e vagina. Porém, como a exposição precoce a hormônios esteróides é capaz de alterar permanentemente vários órgãos reprodutivos, torna-se questionável se esses agentes também podem interferir com a estrutura e fisiologia da próstata feminina. Com base nesses relatos, o objetivo deste trabalho foi verificar o comportamento da próstata ventral masculina e da próstata feminina de gerbilos adultos que foram expostos ao estrógeno sintético, etinilestradiol durante o desenvolvimento pré-natal, além de analisar a ação pós-natal de andrógenos exógenos sobre ambas as glândulas que foram submetidas à estrogenização do desenvolvimento. Para isso, foram realizadas as análises sorológicas para a quantificação dos hormônios esteróides e as próstatas de gerbilos machos e fêmeas adultos foram submetidas às análises morfológicas, morfométrico-estereológica e imunocitoquímica. Os resultados mostraram que a exposição intra-uterina ao etinilestradiol elevou os níveis séricos de estradiol em ambos os sexos durante a vida adulta, promovendo assim alterações na próstata ventral masculina como neoplasia intra-epitelial prostática (NIP) e irregularidades no epitélio prostático feminino, além de observar o aumento das fibras reticulares e colágenas em ambas as glândulas. A análise imunocitoquímica revelou aumento da imunorreatividade de ?-actina na camada muscular que envolve regiões de lesões prostáticas, e o aumento da imunorreatividade de receptores andrógenos (AR) nas próstatas de ambos os sexos. Os animais que sofreram estrogenização durante o desenvolvimento e mediante aplicação de testosterona na vida pós-natal tiveram os níveis de estradiol normalizado, ainda assim apresentaram lesões prostáticas. Várias dessas alterações são mediadas pelo ER? que foi constatado pela alta imunorreatividade nas próstatas tratadas de ambos os sexos. Com os dados percebeu-se que o tratamento realizado durante o período pré-natal com etinilestradiol promoveu alterações na próstata ventral masculina e na próstata feminina de gerbilos adultos. Porém essas alterações foram mais efetivas na próstata ventral masculina, estando estas associadas aos níveis anormais de estradiol observados nos machos adultos. / Abstract: In males, prostatic morphogenesis is an event controlled by androgens, which act directly via paracrine factors secreted by the mesenchyme. In females, the embryological development of the prostate appears to occur in environment low levels of steroid hormones, but the presence of these hormones in the adult life induces differentiation and secretory activity of prostatic cells. The early exposure to estrogen during the embryonic and neonatal development has been related to disturbances in the permanent morphophysiology of the reproductive system of both sexes. Epidemiological studies indicate that men exposed to estrogenic components during the pre natal development have a higher probability to be infertile and develop and testicular and prostate cancer, while women become more susceptible in developing breast, uterus and vagina cancer. However, as early exposure to steroid hormones can permanently alter various reproductive organs, it is questionable whether these agents can also interfere with the structure and physiology of the female prostate. Based on these reports, the aim of this study was to verify the behavior of gerbil ventral male and female prostates which were exposed to synthetic estrogen ethinylestradiol (EE) during embryonic development, as well as analyze the postnatal action of exogenous androgens on both glands that were submitted to estrogenization. For this were carried out serologic analysis for the measure of steroid hormones and prostate of male and female gerbils adults were subjected to analysis to morphological, morphometric-stereological and immunocytochemical analysis. The results showed that EE intrauterine exposure increased the estradiol serum levels in both sexes, thus promoting alterations in the male prostate such as prostatic intraepithelial neoplasia (PIN) and irregularities in the female prostatic epithelium. Additionally, it was observed an increase of reticular fibers and collagen in both glands. Immunocytochemical analysis revealed increased imunnoreactivity of ?-actin in the muscle layer surrounding regions of prostatic lesions, and increased imunnoreactivity of androgen receptor (AR) in both male and female prostates. The animals that suffered development estrogenization and with the application of testosterone in postnatal life had estradiol levels normalized, still presented prostatic lesions. In addition, in these animals it was verified an increase in the imunnoreactivity of estrogenic receptors (ER?). Several of these alterations are mediated by ER? was verified by high immunoreactivity in prostates treated in both sexes. With the data we noticed that the treatment performed during the prenatal period with ethinyl estradiol promoted alterations in male ventral prostate and female prostate of adult gerbils. But these changes were most effective in the male ventral prostate, these being associated with abnormal levels of estradiol observed in adult males. / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

Orientador: Ronilson Agnaldo Moreno / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-12T08:52:50Z (GMT). No. of bitstreams: 1 Mazuqueli_AnaCristina_M.pdf: 7140095 bytes, checksum: c193ad443d7fe35cf3c6d7b25f3175e8 (MD5) Previous issue date: 2008 / Resumo: O objetivo deste estudo foi avaliar a bioequivalência de duas formulações de acetato de ciproterona e etinilestradiol em drágea vs comprimido (Selene® comprimidos, Laboratório Eurofarma Ltda., formulação Teste e Diane® 35, Schering do Brasil, como Referência) após administração oral em 48 voluntárias adultas sadias. O estudo foi do tipo aberto, randomizado com duas fases, em que as voluntárias receberam uma dose única de acetato de ciproterona 2mg e etinilestradiol 0,035mg . As amostras de plasma foram obtidas em um período total de 240h. As concentrações plasmáticas de acetato de ciproterona e etinilestradiol foram analisadas por um método baseado na cromatografia líquida acoplada ao espectrômetro de massa usando como fonte de ionização photospray ( LC-MS/MS ) utilizando finasterida como padrão interno do acetato de ciproterona e 17-a-etinilestradiol-D4 como padrão interno do etinilestradiol. A concentração plasmática do acetato de ciproterona não teve diferença significante após a administração de ambas as formulações (formulação teste e referência do Diane®35). A média geométrica da razão entre o medicamento teste e referência com 90% IC, foi 90,66% (84,39% - 97,40% ) para Cmax, 96,20% (90,45% - 102,33%) para ASC0-240 e 95,86% (89,81% - 102,31%) para ASC0-inf. Já para o Etinilestradiol a média geométrica da razão entre o medicamento teste e referência com 90% IC, foi de 109,92% (IC 90% = 102,67% - 117,69% ) para Cmax, 90,63% (83,75% - 98,08%) para ASC0-120 e 83,85% (69,98% - 100,47%) para ASC0-inf. Diante dos resultados encontrados de Cmax e ASC0-t e estando dentro do intervalo de confiança entre 80% e 125% proposto pela Agência Nacional de Vigilância Sanitária (ANVISA) e pelo Food and Drug Administration (FDA), conclui-se que o Acetato de Ciproterona 2mg e o Etinilestradiol 0.035mg da Eurofarma Laboratórios Ltda. em comprimido é bioequivalente ao Diane®35 da Schering do Brasil, de acordo com sua taxa e extensão de absorção. / Abstract: The aim of this study was to assess the bioequivalence of two cyproterone acetate + ethinylestradiol tablet formulations (Selene® tablet formulation elaborated by Eurofarma Laboratórios Ltda., Brazil, as test formulation, and Diane ® 35 tablet formulation by Schering of Brazil, as reference formulation) after their oral administration to 48 healthy adult females. The study was conducted using an open, randomized two-period crossover design, in which twenty-four healthy volunteers received a single oral dose of cyproterone acetate + ethinylestradiol (2mg + 0.035mg) tablet. Plasma samples were obtained over a 240-hour period. Plasma cyproterone acetate + ethinylestradiol concentrations were analyzed by a method based on liquid chromatography by positive-ion photospray ionization (LC-MS/MS), using finasteride as internal standard of cyproterone acetate and 17-a-ethinyl estradiol-D4 as internal ethinylestradiol standard. The plasma concentration of CYP acetate did not differ significantly after the administration of both formulations (test formulation and the reference Diane®), according to the geometric mean ratio between the test and reference formulations, with 90% CI: 90.66% (84.39% - 97.40% ) for Cmax, 96.20% (90.45% - 102.33%) for ASC0-240 and 95.86% (89.81% - 102.31%) for ASC0-inf. Conversely, the geometric mean ratio between the test and reference formulations for ethinylestradiol, with 90% CI, was 109.92% (CI 90% = 102.67% - 117.69% ) for Cmax, 90.63% (83.75% - 98.08%) for ASC0-120 and 83.85% (69.98% - 100.47%) for ASC0-inf. Considering the results of Cmax and ASC0-t within the confidence interval between 80% and 125% proposed by the Brazilian National Agency for Sanitary Surveillance (ANVISA) and for the US Food and Drug Administration (FDA), it was concluded that the cyproterone acetate 2mg and ethinylestradiol 0.035mg by Eurofarma Laboratórios Ltda. in tablet is bioequivalent to the Diane®35 by Schering of Brazil, according to its absorption and extension rate. / Mestrado / Mestre em Farmacologia

Orientadores: Sebastião Roberto Taboga, Fernanda Cristina Alcântara dos Santos / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T18:00:07Z (GMT). No. of bitstreams: 1 Perez_AnaPauladaSilva_D.pdf: 9263858 bytes, checksum: 6ed11b7c4d0102ec555e0f333c5a35e7 (MD5) Previous issue date: 2014 / Resumo: Os disruptores endócrinos (DE) são agentes exógenos que interferem no funcionamento do sistema endócrino. O 17?-etinilestradiol (EE), um importante componente dos contraceptivos orais é um exemplo de DE. Alguns estudos com roedores machos e fêmeas relataram que a exposição aos DE durante o período pré-natal foi capaz de eliciar proliferações patológicas no sistema reprodutor, incluindo a próstata do animal adulto. Entretanto, pouco se sabe sobre a real ação do estrógeno nas próstatas de machos e fêmeas, principalmente quando se leva em consideração o comportamento de ambas às próstatas durante o desequilíbrio dos níveis de hormônios esteroides que ocorre na puberdade e durante o envelhecimento dessas glândulas. Assim o presente estudo, teve como objetivos avaliar por análises morfológicas, sorológicas e imunohistoquímica quais foram os efeitos da exposição à baixa dose de EE durante os períodos pré-natal e puberal sobre a próstata ventral masculina e na próstata feminina de gerbilo senil. Deste modo, nós dividimos os grupos experimentais de acordo com o período de exposição ao EE (15µg/kg/dia). EE/PRÉ durante o período pré-natal, EE/PUB durante a puberdade e o EE/PRÉ-PUB durante o período pré-natal e puberdade. A exposição à estrógenos sintéticos durante o desenvolvimento afeta o eixo hipotálamo-pituitária gonadal, alterando a produção de hormônios esteroides. Os resultados revelaram que a exposição ao EE durante o desenvolvimento prostático alterou os níveis de hormônios esteroides, diminuindo os níveis de testosterona nos machos senis dos grupos EE/PRÉ e EE-PRÉ/PUB e aumento, nas fêmeas senis do grupo EE/PRÉ. Os níveis de estradiol aumentaram nas fêmeas do grupo EE/PRÉ-PUB. A interação epitélio-estroma também foi afetada pela exposição ao EE durante o desenvolvimento, dado evidenciado pela diminuição da imunorreatividade de ?-actina de músculo liso em regiões com presença de lesões invasivas, principalmente na próstata ventral de macho senil. A frequência de células positivas de p63 diminuiu na próstata ventral masculina do grupo EE/PRÉ, provavelmente a camada basal diminui em locais onde se observa foco com NIP e, aumentou na próstata feminina do grupo EE/PUB. Entretanto, esses dados mostraram que a próstata ventral de machos senil foi mais sensível aos efeitos da exposição ao EE, comparado à próstata de fêmeas senis. A senescência é caracterizada pela queda dos hormônios sexuais¸ e nessa fase aumenta as doenças prostáticas em machos e fêmeas. A exposição ao EE durante fases críticas como o pré-natal e a puberdade acentuaram as alterações na estrutura glandular da próstata e aumentaram o desenvolvimento de lesões prostáticas na senescência. Assim como o período pré-natal, o puberal também foi considerado uma fase crítica na exposição ao EE sobre a próstata de gerbilos machos e fêmeas senis. O consumo de EE durante a gestação ou na puberdade altera significativamente a saúde prostática masculina e feminina durante o envelhecimento, e o gerbilo foi considerado um bom modelo para esse estudo / Abstract: Endocrine disruptor (ED) are exogenous agents that interfere in the endocrine system function. 17?-ethinylestradiol, an important component of oral contraceptives is an example of ED. Studies with male and female rodents have reported that exposure to ED during the prenatal period is able to elicit aberrant pathological proliferations in the reproductive system, inclusive in the prostate of the adult animal. However, the amount known about the actual action of estrogen on male and female prostate, mainly as is the behavior of both prostates during imbalance between androgen and estrogen that occurs in pubertal period and during senescence of these glands. Thus the present study aimed to evaluate by morphological, serological, histopathological and immunohistochemical methods, as the exposure to low dose of ethinylestradiol during the prenatal and pubertal periods acts on ventral male prostate and female prostate of senile gerbil. Thus, we divided the experimental groups according to the period of exposure to EE (15?g/kg/day). EE/PRE during the prenatal period, EE/PUB during puberty and EE/PRE-PUB during the prenatal period and puberty. Exposure to synthetic estrogens during development affects the hypothalamic-pituitary-gonadal axis this alters the production of steroid hormones. The results showed that exposure to EE during developing prostate changed steroid hormones levels, decreasing testosterone levels in senile male of EE/PRE and EE-PRE/PUB groups and increased in senile female of EE/PRE group. The estradiol levels enhanced in females of EE /PRE-PUB group. In addition, EE exposure during the prenatal and pubertal periods altered the immunoreactivity of AR, ER? and ER?, as the function of these receptors are critical for prostate development, changes these signaling pathways contributed to increase of development of lesion and inflammation prostate in males and females during senescence. The stromal-epithelium interaction was also affected by exposure to EE during developing, was observed by decreased immunoreactivity of smooth muscle ?-actin in regions where noted invasive lesions, mainly in the ventral male prostate of senile gerbil. Frequencies positive cells of p63 decreased in the ventral male prostate of EE/PRE group, the basal layer decreases in locals with NIP focus, and these frequencies increased the female prostate EE/PUB group. However, these data showed that the ventral male prostate of senile gerbil was more sensible to effects of exposure to EE compared to female prostate. Senescence is characterized by reducing of sexual hormones, in this phase increases the prostatic diseases in males and females. Exposure to EE during critical periods as prenatal and puberty accentuated the changes in prostate glandular structure and increased the developing prostatic lesions in senescence. As prenatal period, pubertal was also considered a critical phase during the exposure to EE on male and female prostate of senile gerbil. The use of EE during gestational or puberty phases significantly alters male and female prostate health during aging, and the gerbil was considered a good model for this study / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

No description available.

Exposure to exogenous estrogens such as synthetic 17α-ethinyl estradiol (EE) occurs via multiple sources (i.e. hormonal contraceptives, environmental contamination, hormone replacement therapy). The natural estrogen, 17β-estradiol (E2), is a well-studied immunomodulatory hormone at both environmental and pharmacologic levels. Conversely, little data exist regarding the immune effects of EE at either environmentally-relevant exposure levels or at pharmacological levels. Further, EE is delivered to patients in a clinical setting via different routes of exposure (e.g. subcutaneous or oral). Many key questions in relation to potential immunological effects of EE are unanswered. Important variables in estrogen-modulation of the immune system include: (i) dose, (ii) age, (iii) gender, and (iv) route of exposure. Thus, pertinent questions emerge. Does exposure to EE at low concentrations for a subacute duration affect the immune or reproductive systems? Are the effects similar in both hormones and between sexes? Are these effects similar in juvenile and aged mice? How do the effects compare across two common routes of exposure (subcutaneous versus oral)? To address these questions, three separate studies were performed. In the first study, we investigated whether very low, but environmentally relevant, doses of EE, E2 (10 ng/kg body weight), or vehicle orally administered every other day for 21 days to young (6 week-old) and aged (>15 month-old) C57BL/6 mice had immunomodulatory effects. As expected, significant gender and age-related differences were noted with regard to thymus weight, thymocyte recovery, spleen weight, and splenocyte recovery. However, low dose treatment of either E2 or EE had no marked effects on the thymus or spleen organ to body weight ratios, cell numbers, or lymphocyte subsets. Low dose oral estrogens did not alter the ability of activated splenocytes to induce interferon-γ or nitric oxide. No effects on male reproductive organ to BW ratios of young or aged mice were found. Similarly, with the exception of E2-stimulating effects on the female reproductive tract of young mice, there were no pronounced effects in females. In separate studies, intact juvenile female and male C57BL/6 mice were given daily subcutaneous (second study) or oral (third study) doses of either EE or E2 (0.04, 0.4, or 4.0 μg per 25 g BW) for 21 days. In the subcutaneous exposure study, both EE and E2 morphologically altered uterine and seminal vesicle weights. However, EE had a more pronounced effect compared to E2, especially in males, even at the lowest dose administered. Additionally, like E2, EE induced thymic atrophy in both sexes. In female mice, thymic atrophy and thymic cellularity were significantly decreased by subcutaneous EE and E2 at doses of 0.4 and 4.0 μg/25 g body weights. EE elicited significantly more pronounced thymic atrophy-inducing effects compared to E2 at the 4.0 μg/25g dose. In males, thymocyte cellularity was decreased by both subcutaneous EE and E2 only at the highest dose tested (4.0 μg/25 g body weight), whereas only 4.0 EE significantly decreased thymus to body weight ratios. Neither splenic weights, splenic cellularity, nor splenic cell phenotype were affected by either estrogenic compound regardless of route of exposure. Oral exposure of EE or E2 did not induce marked immunological effects. Collectively, these data demonstrate that select thymic and reproductive endpoints are significantly altered following a 21-day subcutaneous exposure to either EE or E2 and that the thymus is a more sensitive target than the spleen with regard to subacute exposure to EE. In addition, EE at a comparable dose was more potent than E2 at exerting thymic and reproductive organ morphological alterations. Furthermore, route of administration is critical, as subcutaneous exposure induced far more dramatic thymic and reproductive morphological alterations than did oral administration. Future studies need to address the precise mechanism through which EE induces thymic atrophy and diminished thymus cellularity. Are these effects mediated directly through the thymus, perhaps through estrogen-induced increased thymocyte apoptosis or alterations to thymic epithelial cells? Or could EE be mediating alterations via bone marrow stem cells targeted for distribution to the thymus? Our novel findings regarding EE-induced effects on the thymus are of health significance and set the stage for future work. / Master of Science