The effect of forced molt on pituitary function and other endocrine parameters was investigated in three year old hens subjected to a dietary forced molting procedure. In addition to molting, fasting caused cessation of egg production, body and organ weight loss, alterations in hormone secretion and morphological changes in some endocrine glands. Body and ovary weights decreased but returned to normal with ad libitum feeding. Pituitary, thyroid and adrenal weights were not affected but serum hormone levels measured by RIA revealed a decrease in LH, FSH and PRL and increases in TSH, T₃ and GH all of which returned to higher levels with ad libitum feeding. Serum P₄ levels remained low (and egg-laying stopped) until ad libitum feeding was resumed and then increased and egg-laying returned to a typically productive level. Serum ACTH and T₄ increased with fasting and remained elevated. Gonadotrophs and corticotrophs increased in numbers with fasting and/or food restriction but thyrotrophs, somatotrophs and lactotrophs decreased. Correlations between cell populations and serum hormone levels was quite common. Colloid-filled follicles resembling a hypertrophic thyroid gland occurred throughout the pituitary pars distalis. Granules appear to be discharged into the follicular lumen through exocytotic pores in the apical plasmalemma of follicular cells. Lactotrophs, corticotrophs and somatotrophs are commonly arranged in follicles or clusters. PRL-containing granules are in the center of some follicles and are concentrated near pituitary cysts. Pituitary cysts, lined with ciliated epithelium and sparse mucous cells, are more prevalent in fasted hens and decline with the resumption of feeding. Reduced lactotroph populations and presumptively degenerated lactotrophs in cyst lumens are correlated with reduced serum PRL levels. Necrotic cells occurred in the pituitary parenchyma of fasted birds but dilated RER in the thyrotrophs of fasted hens indicate enhanced activity of these cells. Ultrastructural evidence presented here indicates that pituitary secretion by lactotrophs occurs both intraluminally and perivascularly.

Investigations have shown that the hypothalamus and pituitary respond to decreases in body temperature by stimulating thyroid release of T_3 and T_4 . This study was designed to bypass the control of the hypothalamus and pituitary gland and investigate the direct effect of temperature on the thyroid gland. Hypothermia was by an in vivo isolated perfusion of the thyroid gland. Radio-immunoassay was used to measure T_3 and T_4 concentrations. Significant increases were observed in animals perfused between 36º and 25ºc. These results indicate that the thyroid gland is directly effected by decreased temperature and that it is capable of exerting control over body temperature independent of the hypothalamus and pituitary gland. Lower perfusion temperatures produced no significant increases.

A parte ventral da área pré-óptica medial (MPOA) apresenta o RNAm do prépró-hormônio concentrador de melanina (ppMCH) e o MCH apenas durante a lactação, especialmente entre os dias 19º e 21º. Fibras imunorreativas ao MCH (MCH-ir) e ocitocinérgicas (OT-ir) de origem desconhecida transitam na lâmina interna da eminência mediana (MEi) e na hipófise posterior (PPit). Utilizamos ratas lactantes da linhagem Long-Evans para identificar a origem dessas fibras, caracterizar sua relação na MEi e PPit e quantificar o ppMCH e OT na PPit. A imuno-histoquímica mostrou que não há colocalização entre as fibras MCH-ir e OT-i e há uma proximidade entre suas fibras na MEi e PPit. A dupla hibridização in situ e imuno-histoquímica mostrou que os neurônios retrogradamente marcados com FG após injeção intravascular expressam o RNAm do ppMCH na MPOA e no núcleo paraventricular do hipotálamo. O Western Blotting mostrou uma maior presença do ppMCH na PPit no 19º dia de lactação. Os dados sugerem que o MCH atua no controle neuroendócrino para o término do período de lactação. / The ventral part of the medial preoptic area (MPOA) has been described as the novel harbor of the expression of prepro-melanin-concentrating hormone (ppMCH) mRNA and MCH peptide, only during the end of lactation, especially between the 19th and 21st days. MCH-ir and OT-ir fibers are described as passing in the internal layer of the median eminence (MEi). However, the origin of MCH-ir fibers and its possible relationship with the OT-ir fibers are not known. Long-Evans rats were used to identify the origin of these fibers and characterize their relationship into MEi and PPit and quantify ppMCH and OT in PPit. Immunohistochemistry showed no colocalization between MCH-ir and OT-ir fibers, but a closeness between these fibers into MEi and PPit. Using a combination of in situ hybridization and immunohistochemistry we have showed that neurons retrogradely labeled with FG after intravascular injection express the ppMCH mRNA into MPOA and paraventricular nucleus of the hypothalamus. The Western blotting showed an increase of ppMCH in the PPit parallel with a decrease of OT-ir on the 19th day of lactation. The data suggest that MCH acts on the neuroendocrine control towards the end of the lactation period.

A partir da hipófise de Astyanax altiparanae foram clonados e caracterizados os cDNAs completos para fshb, lhb e gpha. Das gônadas, foram clonados os cDNAs para fshr e lhr. As análises filogenéticas destes genes demonstram uma proximidade com as sequências homólogas das ordens Siluriformes e Cypriniformes. Por meio de qPCR, detectamos que a expressão dos mRNAs para as gonadotropinas foi restrita à hipófise, ao passo que dos receptores foi restrita às gônadas. Foi detectado que os mRNAs/proteínas para subunidades beta são expressas por diferentes populações de células gonadotrópicas. Nas gônadas, ambos receptores foram localizados nas células de Sertoli e Leydig, bem como nas células foliculares e da teca de oócitos a partir de crescimento secundário. Então, os níveis de expressão gênica das subunidades das gonadotropinas e seus receptores, juntamente como os níveis plasmáticos de esteroides sexuais foram avaliados e relacionados com a cinética da gametogênese durante o ciclo reprodutivo anual de machos e fêmeas em cativeiro. / From Astyanax altiparanae pituitaries, we cloned the full-leght cDNAs coding for fshb, lhb e gpha. From gonads, we cloned the full-length cDNAs for fshr and lhr. Phylogenetic analysis revealed that all five sequences showed the highest identity degree with homologous sequences from Siluriformes and Cypriniformes, respectively. Using qPCR, we observed that gonadotropin subunits expression were restricted to the pituitary gland, just like their receptors were restricted to the gonads. We also observed that both gonadotropin beta subunits mRNAs/proteins are expressed by distinct populations of gonadotropes at pituitary. In the gonads, both receptors were detected on Sertoli and Leydig cell, as well as on ovaries were located on follicular and theca cells, in oocytes starting from secondary growth. Then, gene expression levels of gonadotropins subunits mRNAs and their receptors were assessed, in parallel to plasma level of sex steroids, and evaluated according to gemetogenesis during the annual reproductive cycle of males and females kept in captivity.

A avicultura brasileira tem alcançado altos índices de desempenho na produção de carne e ovos, como resultado da atualização constante de tecnologias no setor. A biotecnologia vem contribuindo nesse sentido, atuando especialmente em programas de seleção de animais com maior potencial de desenvolvimento e crescimento. Como toda a fisiologia animal é controlada direta e/ou indiretamente pela hipófise e hipotálamo, este trabalho propôs identificar e analisar genes expressos nestas estruturas de galinhas de duas linhagens divergentes quanto ao potencial de crescimento e avaliar a expressão dos genes correspondentes a transcritos cuja identidade não pôde ser revelada (sem similar nos bacos de dados), uma vez que estes podem representar possíveis genes novos. Para isto, foram construídas e analisadas bibliotecas a partir da hipófise e hipotálamo de aves de 21 dias de idade de uma linha macho de corte (TT) e uma linhagem de postura (CC), provenientes da Embrapa Suínos e Aves. Um total de 4.286 ESTs válidas foi obtido (no mínimo150 pb com qualidade PHRED acima de 20), correspondendo a 2.133 ESTs da biblioteca da linhagem TT e 2.153 ESTs da biblioteca da linhagem CC. O exercício de montagem, via programa Cap3, revelou 3.074 seqüências únicas, sendo 1.643 da biblioteca da linhagem TT e 1.649 da CC. Estas seqüências únicas foram automaticamente classificadas, de acordo com as categorias do GeneOntology, sendo que as seqüências de ambas as bibliotecas apresentaram uma distribuição similar entre os termos. Após montagem das ESTs e análise do padrão de expressão digital das seqüências constituintes, dos 389 contigs obtidos, 194 foram compostos por seqüências diferencialmente expressas entre as bibliotecas. Foram detectados 28 contigs contendo SNPs linhagem específicos, sendo 52 SNPs TT específicos e 25 CC específicos. Um total de 146 ESTs não pôde ter sua identidade revelada, porém destas, 133 puderam ser localizadas no genoma da galinha e apresentaram pelo menos uma fase de leitura aberta (ORF). Após análise de expressão gênica, os genes correspondentes a 78 destas ESTs sem identidade apresentaram-se diferencialmente expressos entre pelo menos dois dos tecidos de aves de uma linhagem comercial de corte de 21 dias de idade estudados: hipófise, hipotálamo, cérebro, fígado e músculo. Os resultados apresentados são promissores e merecem ser investigados em estudos futuros com o objetivo de identificar marcadores moleculares para programas de seleção e melhoramento animal. / The brazilian aviculture has reached a high development level in both meat and egg production as a result of constant technological atualization in the sector. Biotechnology can contribute in this way acting in selection programs of animals that show higher growth and development potential. The global animal physiology is direct or indirectly controlled by pituitary and hypothalamus. The aim of this work was to identify and analyse genes expressed in these structures of two divergent line chickens according to growth potential and evaluate the gene expression of corresponding transcripts classified as "no hit", once these ESTs could represent new genes. In this way, two pituitary and hypothalamus libraries of 21 days broiler (TT) and a layer (CC) chickens supplied by Embrapa Swine and Poultry National Research Center were constructed and analysed. A total of 4,286 valid ESTs was obtained (showing at least 150 bp with PHRED quality above 20) corresponding to 2,133 ESTs of TT line library and 2,153 ESTs of CC line library. The clustering process by Cap3 resulted in 3,074 unique sequences corresponding to 1,643 TT library sequences and 1,649 of CC sequences. These unique sequences were automatically annotated according GeneOntology categories and both library sequences showed a similar distribution between the terms. After ESTs clustering and northern digital analysis, 389 contigs were obtained – 194 of them showed differentially expressed sequences between the libraries. A total of 28 contigs showed line specific SNPs, corresponding to 52 TT specific SNPs and 25 CC specific SNPs. 146 ESTs were classified as "no hit" but 133 of these sequences were localized in chicken genome and showed open reading frame (ORF). After gene expression analysis, the genes of 78 "no hit" ESTs showed different expression level between the five tissues of commercial broilers with 21 days old: pituitary, hypothalamus, brain, liver and muscle. These results are promising and must be more investigated in future studies to identify molecular markers for use in animal selection and improvement programs.

Protocolos de sucesso para a maturação in vitro de oócitos de peixe são importantes, uma vez que é necessário para garantir uma fertilização bem sucedida, formação do zigoto, crescimento do embrião e seu completo desenvolvimento. Em algumas espécies, a eficiência deste processo ainda é muito baixa ou restrita a poucas substâncias que podem ser utilizadas. Assim, pesquisou-se a utilização de hormônios alternativos ao protocolo já existente para maturação in vitro de ovócitos de zebrafish. O objetivo foi avaliar a eficiência do extrato de hipófise de carpa (EHC), dos hormônios folículo estimulante (FSH) e luteinizante (LH) para fazer a maturação dos ovócitos estádio III de zebrafish. Os oócitos estádio III foram colocados em meio de cultivo Leibovitz modificado, suplementado com soro fetal bovino e adicionado o hormônio correspondente a seu tratamento (T1-controle; T2-16 μg/ml de EHC; T3- 32 μg/ml de EHC; T4- 48 μg/ml de EHC; T5- 64 μg/ml de EHC; T6- 80 μg/ml de EHC; T7- 0,5 μg/ml de FSH; T8- 0,5 μg/ml de LH e T9- 0,5 μg/ml de FSH e 0,5 μg/ml de LH). A taxa de maturação foi avaliada através da visualização da quebra da vesícula germinal (GVBD). Em todos os tratamentos houve maturação, embora o EHC tenha demonstrado taxas de maturação muito baixas (T2= 12,8%; T3=24,8%; T4=27%; T5=22,7%; T6=9,7%) e inferiores em relação a maior eficiência dos hormônios gonadotrópicos (T7=16%; T8=35%; T9=50%). Além disso foi possível verificar a viabilidade dos oócito através da fertilização in vitro do melhor tratamento (T9) com uma taxa de eclosão e desenvolvimento em larva de 60%. Os resultados da maturação in vitro utilizando estes indutores hormonais em oócitos estádio III de zebrafish mostraram-se promissores, e reforçam as perspectivas para o aprimoramento e uso desta técnica para produção in vitro de embriões viáveis. / Successful protocols for maturation of oocytes are important, as it is necessary for ensuring successful fertilization, zygote formation, embryo growth and full development. In some species the efficiency of in vitro maturation is still very low or is still restricted to a little amount of substances which can be used for the matter. Thus, we studied the use of alternative hormones to the existing protocol for in vitro maturation of zebrafish oocytes. The aim of this study was to evaluate the efficiency of the use of carp pituitary extract (CPE), the follicle stimulating hormone (FSH) and luteinizing hormone (LH) to oocyte maturation stage III of zebrafish. Oocytes stage III were placed in modified Leibovitz culture medium, suplemented with fetal bovine serum and added to the correnponding hormone treatment (T1-control; T2-16 g / ml of CHE; T3 32 g / ml of CHE, T4 - 48 g / ml of CHE; T5- 64 g / ml of CHE; T6- 80 g / ml of CHE; T7- 0.5 g / ml of FSH, T8 0.5 mg / ml of LH and T9- 0.5 g / ml of FSH and 0.5 mg / ml LH). The maturation rate was assessed by the germinal vesicle break down (GVBD). In all cases there was maturation, though the EHC has demonstrated fairly low maturation rate (T2= 12,8%; T3=24,8%; T4=27%; T5=22,7%; T6=9,7%) and lower in relation of the high efficiency presented by the gonadotropic hormones (T7=16%; T8=35%; T9=50%). In addition it was possible to verify the viability of the oocyte through IVF of the best treatment (T9) with a result of 60% of hatching and larvae development rate. The results of maturation in turn using this hormones in stage III oocytes of zebrafish proved promising, and enhance the prospects for improvement and use of this technique for in vitro production of viable embryos.

A ocorrência de síndrome de Cushing (SC) durante a gestação é rara, e está associada com significativa morbidade e mortalidade materna. O diagnóstico da SC durante a gestação é, por vezes, problemático pela superposição de achados clínicos e laboratoriais com a gestação normal. Em relação aos aspectos laboratoriais, a ativação do eixo hipotálamo-hipófise-adrenal (HHA) materno na gestação altera parâmetros e testes utilizados para o rastreamento da SC. Desta forma, a confirmação do hipercortisolismo é mais difícil na gestação, particularmente no segundo e terceiro trimestres. Dentre os exames de rastreamento, o cortisol salivar noturno (CSN), por indicar alteração no ritmo circadiano de secreção de cortisol, que é característico da SC, tem sido considerado método importante para diferenciar grávidas com SC daquelas com gravidez normal, que apresentam ritmo circadiano preservado. No entanto, os valores de referência do CSN na gravidez não estão estabelecidos. Desta forma, o presente estudo tem como objetivo determinar os valores de referência de CSN em gestantes no primeiro, segundo e terceiro trimestres tendo como grupo controle mulheres não grávidas e pacientes portadoras de doença de Cushing (DC), com a finalidade de contribuir para o diagnóstico diferencial entre o hipercortisolismo fisiológico e o patológico durante a gestação. Para tanto, o CSN foi mensurado por meio do ensaio imunoenzimático (ELISA) em três grupos de indivíduos: 85 gestantes (grupo gestante), 33 mulheres não grávidas (grupo controle) e 25 mulheres não grávidas com DC (grupo DC). Observou-se menor concentração do CSN no grupo controle (mediana de 0,07 ug/dL) e as maiores no grupo DC (mediana de 0,51 ug/dL). Notou-se tendência de aumento das medianas do CSN no decorrer dos trimestres da gestação (primeiro trimestre: 0,08 ug/dL; segundo trimestre: 0,10 ug/dL; terceiro trimestre: 0,15 ug/dL). Em relação ao grupo controle, o CSN mostrou aumento de 1,1 vezes no primeiro trimestre, 1,4 vezes no segundo trimestre e de 2,1 vezes no terceiro trimestre da gestação. No grupo DC, o CSN foi significantemente superior ao do grupo controle e ao terceiro trimestre gestacional. Observou-se, ainda, que os valores de CSN foram significantemente superiores no terceiro trimestre da gestação em relação ao grupo controle. No presente estudo, determinamos valores de referência para o CSN na gestação, sendo o limite superior para o CSN nos respectivos trimestres gestacionais: 1º trimestre (0,25 ug/dL), 2º trimestre (0,26 ug/dL) e 3º trimestre (0,33 ug/dL). Os valores de corte do CSN que separaram da melhor forma possível o grupo DC do grupo gestante nos três trimestres foram, respectivamente, 0,255 ug/dL; 0,260 ug/dL e 0,285 ug/dL. A comparação dos valores de corte de CSN de gestantes sem DC com os de pacientes portadoras de DC mostrou alto grau de sensibilidade e especificidade, decrescendo no avançar da gestação. Mesmo no terceiro trimestre, foram de 80% e 93%, respectivamente. Em conclusão, foi observado um aumento progressivo do CSN no decorrer da gestação normal, sendo que concentrações máximas foram encontradas no terceiro trimestre. Um aumento estatisticamente significante do CSN foi encontrado entre o terceiro trimestre de gestação e o grupo controle. Foram estabelecidos valores de referência para o método CSN nos três trimestres gestacionais e foi encontrada uma boa acurácia diagnóstica do CSN na diferenciação entre gestantes normais e pacientes portadores de DC, mesmo no terceiro trimestre gestacional / Cushing\'s syndrome (CS) occurs rarely during pregnancy and is associated with significant maternal morbidity and mortality. Diagnosing CS during pregnancy is sometimes challenging, due to overlapping of clinical and laboratorial findings of the disease with characteristics of normal pregnancy. In addition, activation of the maternal hypothalamic-pituitary-adrenal (HPA) axis during pregnancy interferes with parameters and tests for screening of CS. Therefore, confirmation of hypercortisolism is more difficult during pregnancy, particularly in the second and third trimesters. Among the screening tests, nighttime salivary cortisol (NSC), which can detect changes in the circadian rhythm of cortisol secretion characteristic of CS, has been considered an important method to distinguish pregnant women with CS from normal pregnant women, in whom the cortisol circadian rhythm is preserved. However, NSC reference values in pregnancy have not yet been established. Thus, this study aims to determine the reference values for NSC in pregnant women in the first, second and third trimesters, using non-pregnant women and patients with Cushing\'s disease (CD) as controls, in order to establish values to distinguish between physiological and pathological hypercortisolism during pregnancy. To achieve that, we measured NSC by enzyme-linked immunosorbent assay (ELISA) in three groups of individuals: 85 pregnant women (pregnancy group), 33 non-pregnant women (control group) and 25 non-pregnant women with CD (CD group). Concentration of NSC was lowest in the control group (median 0.07 ?g/dL) and highest in the CD group (median 0.51 ?g/dL). Median NSC showed a trending increase at each consecutive gestation trimester (first trimester: 0.08 ug/dL; second trimester: 0.10 ug/dL; third trimester: 0.15 ug/dL). Compared with the control group, NSC showed increases of 1.1 times in the first trimester, 1.4 times in the second trimester and 2.1 times in the third trimester of pregnancy. Levels of NSC were significantly higher in the CD group compared with the control group and with the third gestational trimester. Values of NSC were also significantly higher in the third gestational trimester compared with the control group. The upper limit values for NSC during pregnancy determined in this study were 0.25 ug/dL in the first trimester, 0.26 ug/dL in the second trimester and 0.33 ug/dL in the third trimester. The cutoff NSC values that best separated the CD group from the pregnancy group in all three trimesters were, respectively, 0.255 ug/dL, 0.260 ug/dL and 0.285 ug/dL. The comparison between cutoff values of NSC in pregnant women without CD with those in patients with CD showed a high degree of sensitivity and specificity, which declined with the advancement of pregnancy. In the third trimester, sensitivity and specificity were still high at 80% and 93%, respectively. In conclusion, a progressive increase in NSC levels was observed during normal pregnancy, with maximum concentrations found in the third trimester. A statistically significant increase in NSC was found in the third gestational trimester when compared with the control group. Reference values were established for the NSC method in the three gestational trimesters with a good diagnostic accuracy of NSC in distinguishing between normal pregnant women, including those in the third gestational trimester, from patients with CD

Prenatal stress exposure (PNS) has detrimental effects on the offspring’s brain and behaviour and has been identified as an etiological factor in inducing cognitive function deficits in rodents and humans. The neural mechanisms are unclear, however reprogramming of the neuroendocrine stress axis, the hypothalamo-pituitary- adrenal (HPA) axis is hypothesised. A psychosocial stressor (residentintruder paradigm) was used to generate PNS rat offspring, making these studies clinically compatible. The hippocampus and the medial prefrontal cortex (mPFC) are critical in regulating cognitive function and also contribute to the negative feedback control of the HPA axis via corticosteroid receptors, including the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). Here the Barnes maze was used to assess spatial learning and memory in male and female PNS offspring during adulthood under different scenarios, including basal and acute and chronic stress conditions. Under basal conditions, PNS was associated with reduced GR and MR mRNA expression in the medial prefrontal cortex (mPFC) and the hippocampus, respectively; suggesting inhibitory feedback control of the HPA axis may be compromised in PNS rats. Moreover, impaired spatial learning was observed in male PNS rats following acute restraint stress. Bilateral lesions of the prelimbic cortex and central administration of an MR antagonist in control rats suggested acute stress-induced learning deficits in PNS males were a result of impaired hippocampus-mediated inhibitory feedback control of the HPA axis. Conversely, a one-week variable stress regimen facilitated spatial learning in PNS rats and this was associated with elevated MR mRNA expression in the dentate gyrus. Moreover, facilitated learning in the PNS rats exposed to chronic stress could be blocked by central administration of an MR antagonist, indicating a facilitatory role of hippocampal MR in spatial learning. In summary, opposite effects of PNS on spatial learning were observed under acute and chronic stress conditions, in which hippocampal MR played a key role in regulating behavioural performance. The effect of age was also examined in PNS rats, and the findings from middle-aged (10-11 months old) rats indicated PNS may accelerate cognitive decline. Sex differences were also studied, with control females’ out-performing males under basal conditions in terms of spatial learning and behavioural flexibility; however following prenatal or chronic stress these sex differences were no longer detected. Furthermore, acute stress impaired spatial learning to a greater extent in females, and this might be attributed to greater HPA axis responses to stress in females compared with males. In conclusion, prenatal stress alters later cognitive performance, in a sex- and stress context-dependent manner. Hippocampal MR plays a critical role in mediating spatial learning, particularly during stress conditions.

Yuen Chi Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 84-106). / Abstracts in English and Chinese. / Abstract (in English) --- p.ii / Abstract (in Chinese) --- p.iv / Acknowledgement --- p.vi / Table of Contents --- p.vii / List of Figures --- p.xii / Symbols and Abbreviations --- p.xv / Scientific names --- p.xvii / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- Pituitary --- p.1 / Chapter 1.2 --- Gonadotropins (GTHs) --- p.3 / Chapter 1.2.1 --- Structure --- p.3 / Chapter 1.2.2 --- Function --- p.5 / Chapter 1.2.3 --- Regulation --- p.7 / Chapter 1.2.3.1 --- Neuroendocrine hypothalamic regulators --- p.9 / Chapter 1.2.3.1.1 --- Gonadotropin-releasing hormone (GnRH) --- p.9 / Chapter 1.2.3.1.2 --- Dopamine (DA) --- p.11 / Chapter 1.2.3.2 --- Endocrine regulators from the gonads --- p.12 / Chapter 1.2.3.2.1 --- Gonadal steroids (T and E2) --- p.12 / Chapter 1.2.3.2.2 --- Negative steroid effect on pituitary GTH regulation --- p.12 / Chapter 1.2.3.2.3 --- Positive steroid effect on pituitary GTH regulation --- p.13 / Chapter 1.2.3.3 --- Paracrine regulators from within the pituitary --- p.14 / Chapter 1.3 --- Activin --- p.14 / Chapter 1.3.1 --- Structure --- p.14 / Chapter 1.3.2 --- Function --- p.16 / Chapter 1.4 --- Follistatin (FS) --- p.17 / Chapter 1.4.1 --- Structure --- p.17 / Chapter 1.4.2 --- Function --- p.19 / Chapter 1.5 --- Temporal Variations in the GTH Expressional and Releasing Profile and Sex Steroid Level in the Goldfish --- p.19 / Chapter 1.5.1 --- Hormone changes during annual cycle --- p.20 / Chapter 1.5.2 --- Hormone changes during ovulatory cycle --- p.21 / Chapter 1.6 --- Objectives of the Present Study --- p.23 / Chapter Chapter 2 --- "Effects of Dopamine on the Expression of Gonadotropin (GTH) Subunits in the Dispersed Pituitary Cells of the Goldfish, Carassius auratus" --- p.26 / Chapter 2.1 --- Introduction --- p.26 / Chapter 2.2 --- Materials and Methods --- p.27 / Chapter 2.2.1 --- Materials --- p.27 / Chapter 2.2.2 --- Primary culture of dispersed goldfish pituitary cells --- p.28 / Chapter 2.2.3 --- mRNA analysis --- p.29 / Chapter 2.2.4 --- Data analysis --- p.30 / Chapter 2.3 --- Results --- p.30 / Chapter 2.3.1 --- Effects of DA on GTH-Iβ and GTH-IIβ expression --- p.30 / Chapter 2.3.2 --- Effects of DA D1 and D2 agonists on GTH-Iβ expression --- p.33 / Chapter 2.3.3 --- Effects of DA D1 and D2 antagonists on DA- inhibited GTH-Iβ expression --- p.33 / Chapter 2.3.4 --- Effects of α-adrenergic agonists on GTH-Iβ expression --- p.33 / Chapter 2.4 --- Discussion --- p.37 / Chapter Chapter 3 --- Seasonal Variation of Activin-regulated Goldfish Pituitary GTH-Ip and GTH-IIβ Expression and Evidence for the Involvement of Gonadal Steroids --- p.40 / Chapter 3.1 --- Introduction --- p.40 / Chapter 3.2 --- Materials and Methods --- p.42 / Chapter 3.2.1 --- Materials --- p.42 / Chapter 3.2.2 --- Gonadectomy of the goldfish --- p.42 / Chapter 3.2.3 --- Primary culture of dispersed pituitary cells --- p.43 / Chapter 3.2.4 --- mRNA analysis --- p.43 / Chapter 3.2.5 --- Data analysis --- p.44 / Chapter 3.3 --- Results --- p.44 / Chapter 3.3.1 --- Effects of goldfish activin B on the expression of GTH-Iβ and GTH-IIβ --- p.44 / Chapter 3.3.2 --- Seasonal variation of activin-regulated expression of GTH-Iβ and GTH-IIβ --- p.45 / Chapter 3.3.3 --- Effects of gonadectomy on basal and activin- regulated expression of GTH-Iβ and GTH-IIβ --- p.45 / Chapter 3.3.4 --- Effects of sex steroids on basal and activin- regulated expression of GTH-Iβ and GTH-IIβ in vitro --- p.50 / Chapter 3.4 --- Discussion --- p.57 / Chapter Chapter 4 --- Evidence for the Autocrine/Paracrine Regulation of Gonadotropin Expression by Activin in the Goldfish Pituitary --- p.61 / Chapter 4.1 --- Introduction --- p.61 / Chapter 4.2 --- Materials and Methods --- p.63 / Chapter 4.2.1 --- RNA isolation --- p.63 / Chapter 4.2.2 --- Reverse transcription-polymerase chain reaction (RT-PCR) --- p.63 / Chapter 4.2.3 --- Primary culture of goldfish pituitary cells --- p.63 / Chapter 4.2.4 --- Slot-blot analysis --- p.64 / Chapter 4.2.5 --- Data analysis --- p.64 / Chapter 4.3 --- Results --- p.65 / Chapter 4.3.1 --- Expression of activin βB subunit and activin type IEB receptor in the goldfish pituitary --- p.65 / Chapter 4.3.2 --- Effects of human activin A on goldfish GTH-Iβ and GTH-IIβ expression --- p.65 / Chapter 4.3.3 --- Effects of follistatin on basal and activin- regulated GTH-Iβ and GTH-IIβ expression --- p.69 / Chapter 4.4 --- Discussion --- p.69 / Chapter Chapter 5 --- General Discussion --- p.77 / Chapter 5.1 --- Overview --- p.77 / Chapter 5.2 --- Contribution of the Present Study --- p.78 / Chapter 5.2.1 --- Dopamine as a potential neuroendocrine regulator in the differential regulation of GTH-Iβ and GTH-IIβ expression --- p.78 / Chapter 5.2.2 --- Seasonal variation of the effects of activin on GTH-Iβ and GTH-IIβ expression --- p.79 / Chapter 5.2.3 --- Autocrine/paracrine regulation of GTH expression by activin --- p.79 / Chapter 5.3 --- Future Prospects --- p.81 / References --- p.84

Made available in DSpace on 2016-08-19T18:16:06Z (GMT). No. of bitstreams: 1 Dissertacao Bruno.pdf: 2654529 bytes, checksum: 8a96ae87802691862664f63085d257f5 (MD5) Previous issue date: 2012-03-12 / FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTIFICO E TECNOLÓGICO DO MARANHÃO / Pituitary tumors represent 15% of intracranial neoplasms and are usually benign. The treatment primary is surgical resection with exception for prolactinomas because dopamine agonists are very effective in the treatment these tumors. If surgery does not lead to healing, it is necessary other therapeutic strategy in a attempt to control hormone levels and tumor size reduction. The radiotherapy and medical treatment with somatostatin analogs and agonist dopamine are often used. The study aimed to analyze the presence, distribution and frequency of somatostatin receptor and dopamine receptor (DR2) in pituitary adenomas, and compared their mRNA expression and protein expression. We studied 38 patients with pituitary adenomas. The GH-secreting adenomas showed immunoreactivity more frequent SST2 and SST3 present in 100% of the tumors followed SST5, SST4 and SST1 respectively. Clinically nonfunctioning adenomas SST3 receptor was most widely distributed, present in 13 of 14 tumors followed SST2, SST4, SST1 and SST5 respectively. The mRNA expression of SST2 and SST5 receptor was present in all pituitary adenomas with higher expression of SST2. The DR2 receptor was present and 85% of samples analyzed. In conclusion, the high expression of SST2 in somatotropinomas support the possibility of the use of octreotide as an adjunct therapy in the treatment of acromegalic patients. Patients with clinically nonfunctioning adenomas showed expression of somatostatin receptor and dopamine which indicates the possibility of treating these patients with the somatostatin analogues and / or dopamine agonists. / Os tumores hipofisários correspondem por cerca de 15% das neoplasias intracranianas e são geralmente benignos. O tratamento primário mais comumente utilizado é a cirurgia com exceção para os prolactinomas, devido a eficácia do tratamento com a utilização de agonistas dopaminérgicos. Caso o resultado cirúrgico não leve a ressecção da doença, faz-se necessário o uso de outras modalidades terapêuticas, na tentativa de controlar os níveis hormonais e crescimento tumoral. A radioterapia e o tratamento medicamentoso com os análogos da somatostatina e/ou os agonistas dopaminérgicos são frequentemente utilizados como tratamento adjuvante. O presente estudo teve por objetivo analisar a presença, distribuição e frequência dos receptores da somatostatina e da dopamina (DR2) em adenomas hipofisários e comparar as suas expressões do mRNA e proteicas, através de testes por qPCR em tempo real e por imunohistoquímicos. Foram analisados 38 pacientes diagnosticados com adenomas hipofisários. Os adenomas secretores de GH apresentaram imunoreatividade mais frequente dos receptores SST2 e SST3, presentes em 100% dos tumores, seguidos pelos receptores SST5, SST4 e SST1, respectivamente. Nos adenomas clinicamente não funcionantes o receptor mais amplamente distribuído foi o SST3, presente em 13 dos 14 tumores seguidos pelo SST2, SST4, SST1 e SST5 respectivamente. A expressão do mRNA dos receptores SST2 e SST5 estava presente em todos os adenomas hipofisários estudados, com maior expressão do subtipo SST2. A expressão do mRNA do receptor DR2 foi encontrada em aproximadamente 85% das amostras analisadas. Em conclusão, a elevada expressão do SST2 nos somatotropinomas reforça a possibilidade do uso do octreotide como terapia complementar no tratamento dos pacientes acromegálicos. Os pacientes com adenomas clinicamente não funcionantes apresentaram expressão dos receptores da somatostatina e da dopamina o que indica a possibilidade de tratamento destes pacientes com os análogos da somatostatina e/ou agonistas dopaminérgicos.