Thesis (Ph. D.)--University of Adelaide, Dept. of Animal Science, 1997? / Includes bibliographical references (leaves 169-205).

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 120-134).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 87-114).

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Also available online.

Orientador: Agnaldo Bruno Chies / Coorientador: Oduvaldo Câmara Marques Pereira / Banca: Liliam Fernandes / Banca: Carlos Alan Cândido Dias Junior / Banca: André Sampaio Pupo / Banca: Osni Lázaro Pinheiro / Resumo: As repercussões fisiológicas da redução a longo prazo dos níveis plasmáticos de testosterona têm sido sistematicamente estudadas, uma vez que retratam algumas situações clínicas comumente observadas em homens, tais como o hipogonadismo e o envelhecimento. Um dos importantes alvos das ações androgênicas é o sistema cardiovascular. Particularmente, existe uma importante lacuna de conhecimento em relação à ação da testosterona em leitos venosos. Observamos anteriormente que a orquidectomia promove aumento das ações vasomotoras da fenilefrina em veia porta de rato e que mecanismos relacionados à endotelina-1 poderiam estar envolvidos neste fenômeno. Assim, o objetivo do presente trabalho foi estudar a influência da orquidectomia, seguida ou não de reposição hormonal com testosterona, sobre as respostas vasomotoras de diferentes veias isoladas de rato a agonistas simpatomiméticos. Para isto, utilizaram-se ratos Wistar machos adultos controles e orquidectomizados, seguidos ou não de reposição hormonal (propionato de testosterona, 10mg/kg, i.p., por 3 semanas, com intervalo de 5 dias entre as doses). Destes animais, anéis (4-5 mm) de veias pulmonar, renal, femoral, mesentérica, assim como de artérias, pulmonar, femoral, mesentérica, aorta torácica e abdominal foram estudados em cubas de órgão isolado. Obtiveram-se curvas concentração-resposta para fenilefrina, noradrenalina, clonidina, metoxamina, assim como para endotelina-1, calculando-se pEC50 e resposta máxima (Rmax). Além disso, determinou-se a expressão do mRNA para endotelina-1 e para os receptores ETA e ETB. Os resultados mostraram que a orquidectomia seguida ou não de reposição hormonal não alterou a capacidade contrátil de veia porta frente à clonidina e metoxamina, tampouco frente à noradrenalina na presença de timolol... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The physiological repercussions of a long term reduction in testosterone levels have been systematically investigated, once it can be related with some clinical situations frequently seen in men such as hypogonadism and aging. One of the most important targets of androgen actions is the cardiovascular system. However, androgenic actions upon this system remain controversial especially in venous bed. We have previously observed that orchidectomy induces an increase in vasomotor responses of phenylephrine in rat portal vein. Probably mechanisms related to endothelin-1 could be involved in this phenomenon. Thus, the presented study aimed to investigate the influence of orchidectomy, followed or not by testosterone replacement, upon the response of different isolated veins to sympathomimetic agonists. In this manner, we used control and orchidectomized adult male Wistar rats, with the latter group followed or not by testosterone replacement (testosterone propionate, 10mg/kg, i.p., for 3 weeks, with 5-day intervals between the doses). Rings (3-4 mm) of pulmonary, renal, femoral and mesenteric veins and pulmonary, femoral and mesenteric arteries, as well as thoracic and abdominal aorta were studied in organ baths. Concentration-response curves were obtained to phenylephrine, norepinephrine, clonidine, methoxamine, and to endothelin-1. The maximum response (Rmax) and EC50 were calculated. Furthermore, we determined the mRNA expression of endothelin-1 and the ETA and ETB receptors. The results showed that orchiectomy, followed or not by testosterone replacement did not alter the contractile response of portal vein to clonidine and methoxamine, either face to noradrenaline in the presence of timolol (10-6M) or timolol (10-6M) + yohimbine (10-6M). However, although modifications of portal vein responses to endothelin-1 were not induced by orchidectomy... (Complete abstract click electronic access below) / Doutor

The transcription factor DEAF-1 is the mammalian homologue of a critical Drosophila developmental gene and is essential for neonatal survival in mice. Haploinsufficiency of Deaf-1 in the testis of adult mice was initially thought to cause loss of spermatogenesis and disrupted morphology of the seminiferous tubules, and this heterozygosity was thought to be sufficient to disrupt epigenetic programming in the developing sperm to produce inheritance of testicular defects in both heterozygous and genotypically normal offspring. Although Deaf-1 knockout mice do display disrupted testis structure, infertility at advanced age, hyperproliferation of early germ cells, and abnormal staging of seminiferous tubules, this phenotype was also observed in normal mouse strains that were born in the SIUC vivarium. Mice ordered from a vendor and raised at SIUC did not show testicular defects. This suggests an environmental factor at the SIUC vivarium may act as an endocrine disruptor during embryonic testicular development. Deaf-1-/- mice die soon after birth, often as the result of exencephaly, a gross neural tube defect (NTD). Unlike many mouse models, exencephalic Deaf-1-/- mice do not display a higher incidence of NTDs in females as compared to their male littermates. DEAF-1 promotes Bax-mediated apoptosis; studies using terminal UTP nick-end labeling (TUNEL) suggest a global increase in apoptosis in both exencephalic and normal Deaf-1-/- fetuses during neurulation as compared to their Deaf-1+/+ littermates. This indicates that Deaf-1 is crucial for correct apoptotic patterning during development, which, in turn, is essential for neural tube closure. Finally, cDNA microarray comparison of e14.5 Deaf-1 knockout and wildtype fetuses reveals expression of translation initiation factor 4g3 (Eif4g3) to be downregulated in Deaf-1-/- fetuses. Electrophoretic mobility shift assay using recombinant DEAF-1, and chromatin immunoprecipitation assay of a human cell line confirmed DEAF-1 could bind the eIF4G3 promoter both in vitro and in vivo. Additionally, transcription of the Deaf-1 Antisense Transcript (Das) was found to be significantly downregulated in both e14.5 fetuses and e18.5 fetal brains from Deaf-1-/- mice, suggesting that either lack of Deaf-1 protein or lack of exons 2 through 5 in Deaf-1 knockout mice causes changes in levels of the noncoding RNA that shares Deaf-1's promoter in the mouse.

Made available in DSpace on 2014-06-11T19:32:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-30Bitstream added on 2014-06-13T18:43:04Z : No. of bitstreams: 1 rossignoli_ps_dr_botib_parcial.pdf: 102153 bytes, checksum: d8a43ae97f1572f4a15916ef299ec5df (MD5) Bitstreams deleted on 2014-11-14T12:16:55Z: rossignoli_ps_dr_botib_parcial.pdf,Bitstream added on 2014-11-14T12:17:44Z : No. of bitstreams: 1 000708975.pdf: 551554 bytes, checksum: 67f6e5c14cf654e1e8d2efbd9933a82c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As repercussões fisiológicas da redução a longo prazo dos níveis plasmáticos de testosterona têm sido sistematicamente estudadas, uma vez que retratam algumas situações clínicas comumente observadas em homens, tais como o hipogonadismo e o envelhecimento. Um dos importantes alvos das ações androgênicas é o sistema cardiovascular. Particularmente, existe uma importante lacuna de conhecimento em relação à ação da testosterona em leitos venosos. Observamos anteriormente que a orquidectomia promove aumento das ações vasomotoras da fenilefrina em veia porta de rato e que mecanismos relacionados à endotelina-1 poderiam estar envolvidos neste fenômeno. Assim, o objetivo do presente trabalho foi estudar a influência da orquidectomia, seguida ou não de reposição hormonal com testosterona, sobre as respostas vasomotoras de diferentes veias isoladas de rato a agonistas simpatomiméticos. Para isto, utilizaram-se ratos Wistar machos adultos controles e orquidectomizados, seguidos ou não de reposição hormonal (propionato de testosterona, 10mg/kg, i.p., por 3 semanas, com intervalo de 5 dias entre as doses). Destes animais, anéis (4–5 mm) de veias pulmonar, renal, femoral, mesentérica, assim como de artérias, pulmonar, femoral, mesentérica, aorta torácica e abdominal foram estudados em cubas de órgão isolado. Obtiveram-se curvas concentração-resposta para fenilefrina, noradrenalina, clonidina, metoxamina, assim como para endotelina-1, calculando-se pEC50 e resposta máxima (Rmax). Além disso, determinou-se a expressão do mRNA para endotelina-1 e para os receptores ETA e ETB. Os resultados mostraram que a orquidectomia seguida ou não de reposição hormonal não alterou a capacidade contrátil de veia porta frente à clonidina e metoxamina, tampouco frente à noradrenalina na presença de timolol... / The physiological repercussions of a long term reduction in testosterone levels have been systematically investigated, once it can be related with some clinical situations frequently seen in men such as hypogonadism and aging. One of the most important targets of androgen actions is the cardiovascular system. However, androgenic actions upon this system remain controversial especially in venous bed. We have previously observed that orchidectomy induces an increase in vasomotor responses of phenylephrine in rat portal vein. Probably mechanisms related to endothelin-1 could be involved in this phenomenon. Thus, the presented study aimed to investigate the influence of orchidectomy, followed or not by testosterone replacement, upon the response of different isolated veins to sympathomimetic agonists. In this manner, we used control and orchidectomized adult male Wistar rats, with the latter group followed or not by testosterone replacement (testosterone propionate, 10mg/kg, i.p., for 3 weeks, with 5-day intervals between the doses). Rings (3-4 mm) of pulmonary, renal, femoral and mesenteric veins and pulmonary, femoral and mesenteric arteries, as well as thoracic and abdominal aorta were studied in organ baths. Concentration-response curves were obtained to phenylephrine, norepinephrine, clonidine, methoxamine, and to endothelin-1. The maximum response (Rmax) and EC50 were calculated. Furthermore, we determined the mRNA expression of endothelin-1 and the ETA and ETB receptors. The results showed that orchiectomy, followed or not by testosterone replacement did not alter the contractile response of portal vein to clonidine and methoxamine, either face to noradrenaline in the presence of timolol (10-6M) or timolol (10-6M) + yohimbine (10-6M). However, although modifications of portal vein responses to endothelin-1 were not induced by orchidectomy... (Complete abstract click electronic access below)

Master of Science / Department of Animal Sciences and Industry / Teresa Douthit / Joann Kouba / Gonadotropin-releasing hormone (GnRH-I), as well as its receptor, GnRHR-I, once thought to be localized solely to the hypothalamus and anterior pituitary, have since been detected in the testis of numerous mammals. Another isoform of GnRH, GnRH-II, has been isolated from the testis of numerous mammals and binds a specific receptor, GnRHR-II. Our objective was to establish whether GnRH-I and GnRH-II, along with their specific receptors, are produced and present in the equine testis. Testicular tissue was collected from colts < 2 yr (n = 5) and stallions ≥ 2 yr (n = 10) of age during routine castrations. Total RNA extracted from testicular tissue was reverse transcribed and cDNA was subjected to conventional PCR using gene specific primers for GnRH-I, GnRHR-I, GnRH-II, and GnRHR-II. Protein was extracted and subjected to dot blot and Western blot using antibodies directed against GnRH-I, GnRH-II, GnRHR-I, or GnRHR-II. Transcripts for both ligands and receptors were detected in all testes. Product identity was confirmed by sequencing, which also clarified that unusual band sizes were the result of alternative splicing of GnRHR-II, and the retention of an intron in the GnRH-II mRNA was discovered. Prepro-GnRH-I and prepro-GnRH-II protein was detected in all stallion testes via dot blot technique. On Western blots, testicular samples from colts (n = 4) had 3-fold greater GnRHR-I levels compared to stallions (n = 7; P < 0.022). Conversely, there was a tendency for GnRHR-II protein to be greater in tissue collected from stallions compared to colts (P < 0.0756). Finally semen was collected from mature stallions (9 to 18 yr; n = 4) and purified using a discontinuous gradient. By utilizing immunocytochemistry, GnRHR-II was localized to the connecting piece of mature stallion spermatozoa. This is the first report identifying GnRH-I and -II and their receptors in the equine testis and GnRHR-II on mature stallion spermatozoa. These decapeptide hormones may act via autocrine and/or paracrine signaling to affect steroidogenesis and spermatogenesis in the stallion testis.

Made available in DSpace on 2014-06-11T19:29:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-07Bitstream added on 2014-06-13T18:58:56Z : No. of bitstreams: 1 siqueirafilho_er_me_botfmvz.pdf: 312911 bytes, checksum: 5ab9a919ac68d04b4104d6e5233e180d (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A nutrição é um dos principais fatores que afetam diretamente o metabolismo produtivo e reprodutivo dos animais. Dentre os fatores nutricionais a proteína é um dos elementos mais importantes. Este estudo objetivou a análise de possíveis alterações no sistema reprodutivo de carneiros mediadas pela diferença de proteínas fornecidas na dieta total. Foram instituídas quatro dietas com distintos níveis protéicos: A- (controle) 13,4% PB; 210 g/dia PM; B- 11,4% PB e 187 g/dia PM; C- 17,5% PB e 231 g /dia PM; D-22,4% PB e 215,0 g/dia PM. As coletas de dados foram realizadas em D0; D20; D40; D80; D120. Durante o experimento os animais foram pesados e avaliados quanto a condição corporal; foi feita coleta de sêmen e avaliação em sistema computadorizado (CASA), ultrassonografia e citologia testicular; e dosagem de testosterona, T3 e T4. Os dados obtidos neste estudo, mostraram que a dieta A, não provocou alterações no sistema reprodutivo, portanto foi considerada a mais indicada a carneiros em atividade reprodutiva. / Nutrition is one of the main factors that directly affect the productive and reproductive metabolism of animals. Among nutritional factors, protein is one of the most important elements. The objective of this study was to analyze the possible alterations in the reproductive system of rams mediated by the difference of proteins provided in the total diet. Four diets were established, with distinct protein levels: A- (control) 13,4% CP (Crude Protein); 210 g/day MP (Metabolized Protein); B- 11,4% CP and 187 g/day MP; C- 17,5% CP and 231 g /day MP; D-22,4% CP and 215,0 g/day MP. Data collections were performed in D0; D20; D40; D80; D120. During the experiment, animals were weighted and evaluated concerning body condition; semen collection and evaluation were carried out in computer system (CASA); ultrasound examination and testicular cytology; and hormonal count of testosterone, T3 e T4. The results obtained in this study showed that diet is A did not cause changes in the reproductive system of rams. Therefore, it was considered the most appropriate for rams in reproductive activity.