O objetivo deste estudo foi analisar as concentrações do fator de crescimento semelhante à insulina tipo 1 (IGF1) e insulina (INS) no fluido folicular durante foliculogênese em éguas, e localizar o receptor tipo 1 de IGF (IGF1R) nas paredes foliculares. Durante a estação reprodutiva, 40 éguas mestiças enviadas para abate em matadouro, com idades variando entre 6 e 16 anos foram utilizadas. As éguas foram abatidas de forma humanitária. Os tratos reprodutivos internos foram recuperados dentro de 10 min após o abate, ovários de éguas cíclicas foram separados do resto do aparelho. As éguas foram classificadas em quatro grupos: G1 – Folículo ≤ 13,5 mm e CL identificável; G2 – Folículo de 13,6 - 22,5 mm e CL identificável; G3 – Folículo de 22,6 - 31,5 mm e CL identificável; G4 – Folículo ≥ 31,6 mm e CL difícil de identificar. O fluido folicular (FF) foi aspirado e armazenado a -80 ° C até a sua utilização. Após a punção do FF, um fragmento da porção ventral da parede folicular foi removido para realizar a imunohistoquímica para localização de receptores IGF1R. O IGF1 livre foi determinado por ensaio imunoradiométrico. A INS foi determinada por um radioimunoensaio de fase líquida. A concentração de IGF1 livre e INS no FF aumentou com o crescimento folicular (P < 0,05). O escore imunohistoquímico de IGF1R nas células da granulosa e da teca interna da parede folicular equina em diferentes grupos aumentou (P < 0,05) com aumento folicular. Concluímos que as concentrações de IGF1 livre e INS no FF e de IGF1R em paredes foliculares de éguas aumentam com o crescimento folicular durante a foliculogênese, dando evidência do papel importante do IGF1 e INS no desenvolvimento folicular, e uma interação entre ambos hormônios na fisiologia reprodutiva ovariana. Sendo a égua um modelo de pesquisa para estudos comparativos na dinâmica folicular para consideração em mulheres, a conclusão deste estudo pode ser aplicada, também, a humanos. / The aim of this study was to analyze free type 1 insulin-like growth factor (IGF1) and insulin (INS) concentrations in follicular fluid during folliculogenesis in mares, and to localize type 1 IGF receptor (IGF1R) on follicular walls. During the breeding season, 40 mixed-breed mares sent to slaughter at an abattoir, with ages ranging between 6 to 16 years were used. Mares were humanely slaughtered. Internal reproductive tracts were recovered within 10 min after slaughter; ovaries of cyclic mares were separated from the rest of the tract. Mares were categorized into four groups: G1 – Follicle ≤ 13.5 mm and CL identifiable; G2 – Follicle of 13.6 to 22.5 mm and CL identifiable; G3 – Follicle of 22.6 to 31.5 mm and CL identifiable; G4 – Follicle ≥ 31.6 mm and CL difficult to identify. The follicular fluid (FF) was aspirated and stored at -80°C until use. After puncture of the FF, a fragment of the ventral portion of the follicular wall was removed to perform immunohistochemistry to localize IGF1R receptors. Free IGF1 was determined by immunoradiometric assay. INS was determined by a liquid phase radioimmunoassay. The concentration of free IGF1 and INS in FF increased with follicle growth (P < 0.05). Immunohistochemical score of IGF1R on granulosa and internal theca cells from equine follicular wall on different groups increase (P < 0.05) with follicular raise. We conclude that free IGF1 and INS concentrations in FF and IGF1R in follicular walls of mares increase with follicular growth during folliculogenesis, giving evidence of important role of IGF1 and INS in follicular development, and an interaction between both hormones in ovarian reproductive physiology. As the mare is a model research for comparative studies in follicular dynamics for consideration in women, the conclusion of this study can be applied to humans also.

O transtorno bipolar (TB) é uma doença crônica, altamente incapacitante e sua fisiopatologia não esta bem esclarecida. Apresenta altas taxas de comorbidades clínicas e risco de suicídio trazendo prejuízos e custos significativos para o indivíduo com a doença e para a sociedade. Existem evidências que relacionam o TB à alterações no fator de crescimento semelhante à insulina tipo 1 (IGF- 1) e nos sistemas endócrino e imune. O objetivo deste estudo foi avaliar os níveis séricos de IGF-1 em pacientes bipolares comparados com indivíduos controle e sua relação com a inflamação. Foram selecionados 31 pacientes com TB e 33 controles saudáveis. Foram avaliadas as concentrações séricas de IGF-1, hormônio do crescimento (GH), insulina e fator de necrose tumoral α (TNF-α). Como resultado deste estudo, observamos que os níveis séricos de IGF-1 estavam aumentados em pacientes com TB em relação aos controles (p = 0,001). Não foram observadas diferenças estatisticamente significativas entre os grupos nas dosagens de insulina, GH e TNF- α. Este estudo sugere uma associação entre IGF-1 na fisiopatologia do transtorno bipolar. É possível que este aumento periférico esteja relacionado com um aumento da resistência do IGF- 1 no SNC, reduzindo assim a sua ação neuroprotetora. / Bipolar disorder (BD) is a chronic, highly debilitating and its pathophysiology is not well understood. It offers high rates of clinical comorbidities and suicide risk causing losses and significant costs to the individual with the disease and society. There is evidence that relates to changes in TB-like growth factor type 1 insulin (IGF-1) and the endocrine and immune systems. The aim of this study was to evaluate serum levels of IGF-1 in bipolar patients compared with control subjects and their relationship to inflammation. We selected 31 patients with TB and 33 healthy controls. Serum concentrations of IGF-1, growth hormone, were evaluated (GH), insulin and tumor necrosis factor α (TNF-α). As a result of this study, we observed that serum levels of IGF-1 were increased in TB patients compared to controls (p = 0.001). No statistically significant differences were found between groups in insulin dosages, GH, and TNF-α. This study suggests an association between IGF-1 in the pathophysiology of bipolar disorder. It is possible that this increase is associated with peripheral increased IGF-1 resistance in the CNS, thus reducing its neuroprotective action.

La nutrition au cours de la période postnatale précoce programme l’activité de l’axe somatotrope à l’âge adulte (GH/IGF-1). Une altération de la nutrition chez les souriceaux au cours de la lactation altère la croissance staturo-pondérale de façon permanente et augmente leurs susceptibilités à développer des pathologies cardio-métaboliques à l’âge adulte. La restriction au cours de la lactation induit une diminution des taux plasmatiques en IGF-1 et en leptine. Ceci est associé à une diminution transitoire de l’innervation de l’éminence médiane par les neurones GHRH, ce qui induit une hypoplasie hypophysaire permanente en cellules somatotropes. Durant ma thèse, j’ai étudié l’impact de la nutrition périnatale sur la mise en place de l’axe somatotrope, notamment les mécanismes impliqués dans la régulation du développement des neurones GHRH. Les cultures d’explants de noyaux arqués issus de souriceaux normalement nourris indiquent que l’IGF-1 stimule de façon préférentielle la croissance axonale des neurones GHRH par l'intermédiaire des voies PI3K/AKT et MAPK. La leptine présenterait quant à elle un effet plus global sur les neurones du noyau arqué, stimulant la croissance axonale des neurones GHRH et des neurones orexigène à NPY/AgRP. Les neurones GHRH issus de souris restreintes sont quant à eux résistants à la stimulation de la croissance axonale par l’IGF-1 ou la leptine. Concernant l’IGF-I, cette résistance est associée à une altération des capacités de phosphorylation de la voie PI3K/AKT, tandis que celles de l’IGF-1R et de la voie MAPK ne sont pas altérées. / Nutrition during lactation programs the activity of the somatotropic axis (GH/IGF-1). Alteration of nutrition during the early postnatal period in mice induces increased susceptibility to develop cardiovascular and metabolic pathologies later in life. Nutritional restriction during lactation permanently alters growth of mice. Ten days old restricted pups present decreased plasmatic level of IGF-1 and Leptin. They also present a transient alteration of median eminence innervation by GHRH neurons, which induce a permanent somatotroph cells (GH) hypoplasia in pituitary. The aim of my thesis was to study the impact of nutrition during the perinatal period on the programming of the somatotropic axis, notably the cellular and molecular mechanisms involved in the regulation of GHRH neuronal development. In vitro cultures of arcuate nucleus explants of hypothalamus from normally fed pups indicate that IGF-1 preferentially stimulates axonal growth of GHRH neurons by its signaling pathways PI3K/AKT and MAPK. Leptin present a more global effect and is able to stimulate axonal growth of arcuate nucleus neurons, including GHRH and AgRP neurons. GHRH neurons from restricted pups are resistant to the stimulation of axonal growth by IGF-1 or leptin. Regarding IGF-1, this resistance is associated with an alteration of phosphorylation capacities of the PI3K/AKT pathway, whereas those from IGF-1R and MAPK are not altered.

Insulin/IGF system is a complex network of three similar hormones (insulin, IGF-1 and IGF-2) and their three similar receptors (IR-A, IR-B and IGF-1R,), which play important roles in maintaining basal energy homeostasis of the organism, in growth, development, life-span but also in development of diseases such as diabetes mellitus, cancer, acromegaly or Laron dwarfism. Despite structural similarities between family members, each member have its unique role in the system. Identification of structural determinants in insulin and IGFs that trigger their specific signalling pathways is important for rational drug design for safer treatment of diabetes or for more efficient combating of cancer or growth-related disorders. In this thesis, we focused on identification of such structural determinants in IGF-1. Comparison of our data with parallel studies with IGF-2 and insulin could give a more complex picture of the problem. First of all, we developed necessary methodologies for the preparation of IGF-1 analogues. We developed a new methodology for the total chemical synthesis of IGF-1 analogues based on the solid-phase synthesis of fragments and their ligation by a CuI -catalyzed cycloaddition of azides and alkynes. In parallel, we developed a procedure for a recombinant production of IGF- 1 and its...

Orientador: Anthony César de Souza Castilho / Resumo: A proteína plasmática A associada à gravidez (PAPP-A) é uma metaloprotease, que tem como função aumentar a biodisponibilidade do fator de crescimento semelhante a insulina tipo 1 (IGF-1), um peptídeo com diversas funções em prol do bom desenvolvimento oocitário e embrionário. Assim, a temática principal dessa tese foi utilizar a PAPP-A como um potencializador dos efeitos atribuídos ao IGF-1 durante a PIVE de bovinos. No primeiro artigo, investigamos o efeito da adição de PAPP-A durante a MIV suplementada com soro fetal bovino (SFB). Os complexos cumulus-oócitos (CCOs) foram maturados in vitro por 24 horas na presença ou ausência de SFB e, posteriormente, foram fertilizados e cultivados in vitro. Analisamos o conteúdo lipídico dos oócitos e blastocistos usando o corante Sudan-Black B, a taxa de blastocistos produzidos e a expressão gênica de 96 genes por RTqPCR. Não houve diferença no conteúdo lipídico dos oócitos e blastocistos avaliados, nem na taxa de blastocistos produzidos. No entanto, a presença de PAPP-A durante a MIV diminuiu a expressão de 22 genes relacionados à síntese de lipídeos, apoptose e estresse celular e qualidade embrionária nos blastocistos produzidos. No segundo artigo, os CCOs foram maturados (tratamento na MIV) ou os embriões cultivados (tratamento no CIV) por 24h com adição de IGF-1, IGF-1/PAPP-A, ou na ausência de ambos, em um ambiente estresse-induzido pela presença de menadiona. Avaliamos nos oócitos a progressão da meiose, concentração de espécies r... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Pregnancy-associated plasma protein-A (PAPP-A) is a metalloprotease which role is to increase insulin-like growth factor type 1 (IGF-1), a peptide with several beneficial functions for oocyte and embryo development. Thus, the thesis main subject was using the PAPP-A as an enhancer of IGF-1 attributed-effects during bovine in vitro production. In the first article, we investigated the effects of PAPP-A addition during IVM supplemented with fetal bovine serum (FBS). The cumulus-oocyte complexes (COCs) were in vitro matured for 24 hours in the presence or absence of FBS, and after, in vitro fertilized and cultured. We analyzed the oocytes and blastocysts lipid content by Sudan-Black B staining, the blastocysts yield, and the expression of 96 genes by RTqPCR. There was no difference in oocytes and blastocysts lipid content or in the blastocysts yield. However, the PAPP-A addition during IVM downregulated the expression of 22 genes related to lipid synthesis, apoptosis and cell stress, and embryonic quality in the blastocysts. In the second article, the COCs were matured (IVM treatment) or the embryos were cultured (IVC treatment) for 24 hours with IGF-1, IGF-1/PAPP-A addition, or in absence of both at a stress environment-induced by the menadione addition. We assessed the meiosis progression, reactive oxygen species (ROS) concentration and mitochondrial membrane potential levels in the oocytes using staining techniques. We also analyzed the concentrations of total glutathione (GS... (Complete abstract click electronic access below) / Doutor

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Prostate cancer is the most commonly diagnosed non-skin cancer in men and the second leading cause of cancer death in the United States. Prostate cancer, like many cancers, is a disease that generally requires a long period of time to develop and grow before it becomes detectable. This long period of latency makes prostate cancer a candidate for dietary chemoprevention. Soy and selenium (Se), are associated with a decreased risk of prostate cancer. We previously showed that high dietary intake of selenium (Se) and soy isoflavones decreased the expression of the androgen receptor (AR) and AR-regulated genes in the prostates of healthy rats. In this study we hypothesized that the downregulation of AR and AR-regulated genes would inhibit tumorigenesis in the transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse. Mice were fed one of two stock diets with or without a supplement of Se in a 2 X 2 factorial design. The stock diets provided high or low dietary isoflavones. Mice were exposed to the diets from conception and sacrificed at 18 or 24 weeks of age. Prostate histopathology, urogenital tract (UGT) weight, serum IGF-1 levels, and the expression of AR and AR-regulated genes in the dorsolateral prostate was examined using quantitative PCR and Western blotting. Urogenital tract (UGT) weight was reduced compared to control in all dietary groups containing high Se, isoflavones, or both at 24 weeks (p<0.005). Dietary isoflavones delayed tumor progression and downregulated protein levels of AR, AR-regulated genes, and upregulated the protective FOXO1 and FOXO3a transcription factors. High dietary isoflavones also decreased the phosphorylation of the IGF-1R. The only main effect of Se was the upregulation of AKR1C14 the enzyme that deactivates 5&aplha;-DHT.This study identifies a previously unknown effect of isoflavones in the upregulation of FOXO expression and confirms previous studies of isoflavones' anticancer effects. Further research is needed to find a protective dose or form of Se and to elucidate the mechanism of isoflavones.

Prostate cancer is the second most commonly occurring cancer in men in the United States. Generally, an extended period of time is needed for a mutation to develop into a full scale tumor. Because of this long latency period, lifestyle and environmental factors, such as diet, may play an important role in the development and progression of the disease. Diet is one factor that has been implicated in the risk for developing prostate cancer. We previously showed that diets high in soy isoflavones and selenium (Se) decreased androgen receptor expression and expression of androgen regulated genes in healthy rat prostates. The purpose of this study was to determine whether treatment of soy isoflavones and/or supplemental Se provide chemopreventive effects in the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model of prostate cancer, and whether the timing of the introduction of these nutrients determines protective effects. Male hemizygous C57/BL6 x FVB TRAMP mice were exposed to a diet high in isoflavones, a 4 mg/kg daily bolus of supplemental Se as methylselenocysteine (MSC), or the combination of high isoflavones and MSC starting at one of two time points: conception or 6 weeks of age, and were killed and dissected for prostate tissue, liver, and serum at either 4 weeks or 12 weeks of age (n per dietary treatment = 20: total mice = 240). Treatment with MSC resulted in decreased urogenital tract weight at 4 and 12 weeks. Treatment with MSC and isoflavones, both individually and as a combination, resulted in decreased androgen receptor expression, 5 alpha-reductase levels, and aromatase levels. The combination of MSC and a basal diet high in isoflavones resulted in decreased serum IGF-1 levels in 12 week TRAMP mice. Treatment from conception resulted in greater decreases in urogenital tract weight, 5 alpha-reductase expression, and aromatase expression than treatment from 6 weeks. This study demonstrated that in 12 week TRAMP mice, reductions in risk factors for prostate cancer by treatments of high isoflavones and supplemental Se are maximized by introduction to treatments at conception.

The magnitude of improvements in muscular strength and size are influenced by the volume and intensity of a resistance training program. While it is clearly advantageous for resistance-trained individuals to utilize programming specific to these goals, it not clear which is more important. Therefore the purpose of the present investigation was to determine the effect of focusing on training volume versus intensity on changes in muscle size and strength. Changes in muscular strength and size were examined in 29 resistance-trained men following 8 weeks of resistance training. Participants were randomly assigned to either a high volume (VOL, n = 14, 4 x 10 – 12RM, 1min rest) or high intensity (INT, n = 15, 4 x 3 – 5RM, 3min rest) resistance training program. Lean body mass, lean arm and leg mass, were assessed by dual energy X-ray absorptiometry, while ultrasound images (VL-vastus lateralis, RF-rectus femoris, PM-pectoralis major, and TB-triceps brachii) were used to assess changes in muscle cross-sectional area (CSA) and thickness (MT). Strength was measured by one repetition-maximum (1RM) squat (SQ) and bench press (BP). Changes in muscular (RF & VL) activation in response to increases in submaximal SQ intensity (40-, 60-, 80-, & 100%-1RM) were assessed via surface electromyography. Blood samples were collected at baseline, immediately post, 30min post, and 60min post-exercise at week 3 (WK3) and week 10 (WK10), to assess plasma/serum testosterone, growth hormone (GH), insulin-like growth factor-1 (IGF1), cortisol (CORT), and insulin. Area under the curve analysis revealed a greater (p < 0.05) increase for VOL (WK3: GH & CORT; WK10: CORT) compared to INT. Compared to WK3, WK10 showed reduced responses for VOL (GH and CORT) and INT (IGF1). Significant group differences were observed for changes in lean arm mass (INT: 5.2 ± 2.9%, VOL: 2.2 5.6%) and BP 1RM (INT: 14.8 ± 9.7%, VOL: 6.9 ± 9.0%). Over the course of 8 weeks, our data indicate that trained men would benefit more when focusing on training intensity, rather than volume, for strength and size improvements.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.