No description available.

Opioids are used for the clinical treatment of pain, but can lead to tolerance and addiction. In this project we examined the role of the serotonin (5-HT) system originating from the dorsal raphe nucleus (DRN) during morphine exposure, withdrawal, abstinence and following an acute stressor capable of initiating behavioral relapse. Following four days of morphine exposure rats showed a preference for the morphine paired side of the conditioned place preference (CPP) chamber. After four days of morphine abstinence, rats showed no net preference for the morphine paired side. The next day rats were exposed to forced swim stress and returned to the CPP chamber where they demonstrated stress-induced reinstatement. Utilizing whole-cell patch-clamp we demonstrated an increase in the amplitude of inhibitory post-synaptic currents (IPSCs) in 5-HT DRN neurons, but not non 5-HT DRN neurons of morphine-conditioned subjects. Next the stress neurohormone corticotrophin releasing factor (CRF) was administered in vitro instead of forced swim. We found an increase in CRF-R2-mediated inward current of 5-HT DRN neurons in animals with a morphine history. From this experiment we concluded that morphine history sensitizes 5-HT DRN neurons to the GABAergic inhibitory effects of stress and to some of the effects of CRF. In the next series of experiments we surgically implanted either morphine or placebo pellets in rats for 72 hours to create physical dependence. The pellets were subsequently removed, and animals experienced up to seven days of abstinence with and without forced swim stress exposure. Real time quantitative PCR was used to measure the mRNA levels of genes at multiple points across this timeline. We examined genes involved in trophic support, stress responses and 5-HT regulation. We determined that mRNA levels for brain-derived neurotrophic factor (BDNF) and the BDNF receptor TrkB were downregulated after opiate exposure, and again following seven days of abstinence. Following seven days of abstinence there was a decrease in mRNA levels of the CRF-R1 receptor and an increase in mRNA levels of the CRF-R2 receptor. During acute opiate exposure there was a decrease in mRNA levels for the autoregulatory 5-HT1A receptor. Finally following forced swim, there was an increase in mRNA levels of the 5-HT synthesis enzyme TPH2. Collectively these results indicate that a morphine history in abstinent subjects may produce hypofunctioning of the 5-HT DRN system induced by multiple neurochemical mechanisms and this dysregulation may enhance vulnerability to stress-induced relapse. / Cell Biology

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal. / L'accouchement, l'aboutissement ultime de la grossesse, est un processus bien orchestré mettant en œuvre une pléiade de peptides produits par le placenta. Récemment, la mise en évidence d'une relation entre la durée de la grossesse et la concentration plasmatique du facteur de relâche de la corticostimuline (CRF) a permis de proposer un lien entre ce peptide et l'horloge placentaire déterminant la durée de la grossesse. Or, le neuropeptide Y (NPY), un peptide produit abondamment par le placenta tout au long de la grossesse, stimule in vitro la relâche du CRF par le syncytiotrophoblaste. Puisque ce syncytiotrophoblaste est connu pour être, du moins durant le troisième trimestre de la grossesse, la principale origine du CRF circulant, le but de cette thèse est d'étudier les modalités de cet effet du NPY. Les hypothèses principales ayant balisé cette étude ont été: 1) le syncytiotrophoblaste arbore des récepteurs pour le NPY; 2) un mode de relâche du CRF dépendant du calcium est présent dans le syncytiotrophoblaste et 3) la stimulation de la relâche du CRF par le NPY dans les cellules trophoblastiques implique des voies de signalisation en amont et en aval d'une hausse de la concentration du calcium intracellulaire. En premier lieu, étant donné la nature polaire du syncytiotrophoblaste, les études de liaison ont été effectuées en parallèle sur des membranes d'origine apicale (BBM) et basale (BPM) afin de déterminer s'il y a une ségrégation des sites de liaisons pour le NPY. Les résultats obtenus suggèrent l'existence d'une population mixte de sites de liaison du NPY (Y1 et Y3) se retrouvant exclusivement sur les BBM. Par la suite, les voies de signalisation associées aux récepteurs du NPY ont été explorées sur des préparations de BBM ou sur des cellules trophoblastiques en culture primaire. Les résultats obtenus montrent que dans les BBM, l'interaction du NPY avec le récepteur de sous-type Y1 est couplée à l'activation des phospholipases C-P (PLC-P), ces dernières étant responsables, en partie, d'une activation des protéines kinases C (PKCs). L'autre portion de l'activation de ces PKCs étant attribuable à l'activation des kinases de la position D3 des phosphoinositides (PI3-K). Les résultats obtenus à l'aide des cellules trophoblastiques montrent que le NPY entraîne l'activation de la kinase dépendante du calcium et de la calmoduline de type II (CaMK.11) et des MAP kinases de type ERKv2 (ERKv2). En troisième lieu, afin de vérifier lesquelles de ces voies de signalisation sont impliquées dans le contrôle de la relâche du CRF par le NPY, nous avons, dans un premier temps, caractérisé l'habileté des cellules trophoblastiques à sécréter le CRF. Cette étape importante montre que les cytotrophoblastes issus de placentas à terme, acquièrent, en parallèle avec leur différenciation vers le phénotype apparenté au syncytiotrophoblaste, l'habileté de sécréter le CRF. En dernier lieu, nous avons démontré que le NPY, en interagissant avec des récepteurs de type Y1, induit la synthèse et la relâche du CRF par les cellules trophoblastiques. L'augmentation de la synthèse est, en grande partie, attribuable à l'activation des PLC-P, la relâche subséquente du calcium des réserves intracellulaires et à l'activation de la CaMKII. L'augmentation de la relâche est subséquente à l'activation de PKCs indépendantes du calcium, à l'activation de l'axe initié par les PLC-P et à un influx calcique ne passant pas par les L-VOCC. Intéressement, l'activation directe des L­VOCC avec le Bay K8644, bien qu'entraînant l'activation des CaMKII, favorise la relâche du CRF sans influencer la synthèse du peptide. Pris dans leur globalité, ces résultats illustrent bien la pluralité de la signalisation des récepteurs de sous-type Y 1 et la complexité du contrôle de la relâche du CRF par le NPY. De plus, ces résultats sont une étape importante dans la compréhension des mécanismes qui permettent aux peptides interagissant avec un récepteur couplé aux protéines liant les nucléotides guanyliques (protéines G), sensibles à la toxine pertussique (PTX), de réguler la relâche du CRF.

No description available.

L'objectif de la thèse est de proposer des méthodes permettant d'améliorer l'expressivité des systèmes de synthèse de la parole. Une des propositions centrales de ce travail est de définir, utiliser et mesurer l'impact de structures linguistiques opérant au delà du niveau de la phrase, par opposition aux approches opérant sur des phrases isolées de leur contexte. Le cadre de l'étude est restreint au cas de la lecture de contes pour enfants. Les contes ont la particularité d'avoir été l'objet d'un certain nombre d'études visant à en dégager une structure narrative et de faire intervenir une certain nombre de stéréotypes de personnages (héros, méchant, fée) dont le discours est souvent rapporté. Ces caractéristiques particulières sont exploitées pour modéliser les propriétés prosodiques des contes au delà du niveau de la phrase. La transmission orale des contes a souvent été associée à une pratique musicale (chants, instruments) et leur lecture reste associée à des propriétés mélodiques très riches, dont la reproduction reste un défi pour les synthétiseurs de parole modernes. Pour répondre à ces problématiques, un premier corpus de contes écrits est collecté et annoté avec des informations relatives à la structure narrative des contes, l'identification et l'attribution des citations directes, le référencement des mentions des personnages ainsi que des entités nommées et des énumérations étendues. Le corpus analysé est décrit en terme de couverture et d'accord inter-annotateurs. Il est utilisé pour modéliser des systèmes de segmentation des contes en épisode, de détection des citations directes, des actes de dialogue et des modes de communication. Un deuxième corpus de contes lus par un locuteur professionnel est présenté. La parole est alignée avec les transcriptions lexicale et phonétique, les annotations du corpus texte et des méta-informations décrivant les caractéristiques des personnages intervenant dans le conte. Les relations entre les annotations linguistiques et les propriétés prosodiques observées dans le corpus de parole sont décrites et modélisées. Finalement, un prototype de contrôle des paramètres expressifs du synthétiseur par sélection d'unités Acapela est réalisé. Le prototype génère des instructions prosodiques opérant au delà du niveau de la phrase, notamment en utilisant les informations liées à la structure du conte et à la distinction entre discours direct et discours rapporté. La validation du prototype de contrôle est réalisée dans le cadre d'une expérience perceptive, qui montre une amélioration significative de la qualité de la synthèse. / The aim of this thesis is to propose ways to improve the expressiveness of speech synthesis systems. One of the central propositions of this work is to define, use and measure the impact of linguistic structures operating beyond the sentence level, as opposed to approaches operating on sentences out of their context. The scope of the study is restricted to the case of storytelling for children. The stories have the distinction of having been the subject of a number of studies in order to highlight a narrative structure and involve a number of stereotypical characters (hero, villain, fairy) whose speech is often reported. These special features are used to model the prosodic properties tales beyond the sentence level. The oral transmission of tales was often associated with musical practice (vocals, instruments) and their reading is associated with rich melodic properties including reproduction remains a challenge for modern speech synthesizers. To address these issues, a first corpus of written tales is collected and annotated with information about the narrative structure of stories, identification and allocation of direct quotations, referencing references to characters as well as named entities and enumerations areas. The corpus analyzed is described in terms of coverage and inter-annotator agreement. It is used to model systems segmentation tales episode, detection of direct quotes, dialogue acts and modes of communication. A second corpus of stories read by a professional speaker is presented. The word is aligned with the lexical and phonetic transcriptions, annotations of the corpus text and meta-information describing the characteristics of the characters involved in the story. The relationship between linguistic annotations and prosodic properties observed in the speech corpus are described and modeled. Finally, a prototype control expressive synthesizer parameters by Acapela unit selection is made. The prototype generates prosodic operating instructions beyond the sentence level, including using the information related to the structure of the story and the distinction between direct speech and reported speech. Prototype validation control is performed through a perceptual experience, which shows a significant improvement in the quality of the synthesis.

A resposta comportamental de Imobilidade Tônica (IT) ocorre em situações de perigo intenso, e em situações inescapáveis, como por exemplo,o ataque de um predador. Esta resposta caracteriza-se por perda do reflexo de endireitamento e relativa falta de responsividade aos estímulos ambientais. Estudos consistentes tem demonstrado o envolvimento de distintas áreas encefálicas na modulação desta resposta, entre elas a substância cinzenta periaquedutal, o hipotálamo e a amígdala. Considerando a amígdala em particular, estudos mostraram o envolvimento dos receptores para o fator liberador de corticotropina (CRF) dos núcleos basolateral (BLA) e central (CeA) na modulação da resposta de IT em cobaias. De fato, nas últimas décadas, várias evidências sugerem que o CRF está intimamente correlacionado com comportamento emocional associado ao medo e à ansiedade. Embora seja claro o envolvimento de receptores CRF na modulação do medo, e especificamente na modulação da IT em cobaias, ainda não está esclarecido o envolvimento dos diferentes subtipos de receptores para CRF na modulação emocional. Desta forma, o objetivo deste trabalho foi investigar o envolvimento dos receptores específicos para o fator liberador de corticotropina, CRF1 e CRF2 dos núcleos basolateral (BLA) e central da amígdala (CeA) na modulação da resposta de IT em cobaias.Para atingir estes objetivos, grupos independentes de cobaias, com implante de cânulas-guias dirigidas para o BLA ou para o CeA foram avaliadas no teste de imobilidade tônica, antes e depois da administração dos antagonistas específicos para receptores CRF1 (CP-376395) ou para receptores CRF2 (Astressin 2B), ou depois da administração de CRF precedido ou não dos antagonistas CRF1 ou CRF2. Em adição, para avaliar se as drogas utilizadas alteraram a atividade locomotora, foi realizado o teste do campo aberto, por 5 minutos, após a administração dos antagonistas para receptores CRF1 (CP-376395) e CRF2 (Astressin 2B), em doses capazes de alterar a resposta de IT em cobaias, e de CRF precedido por antagonista CRF1 ou CRF2. Os resultados deste trabalho mostram que o bloqueio dos receptores CRF1 e CRF2 no BLA e no CeA reduziram a duração da resposta defensiva de imobilidade tônica (IT) em cobaias. Inversamente, a ativação destes receptores no BLA e no CeA aumentou o tempo de IT, demonstrado pela administração de CRF nestas regiões amigdalóides. Ainda, os antagonistas específicos para receptores CRF1 e CRF2 foram capazes de bloquear o aumento da duração da IT induzida pelo CRF administrado no mesmo sítio. Estes resultados sugerem que o efeito promovido pelo CRF no BLA e no CeA ocorre por atuação conjunta em receptores CRF1 e CRF2. Em adição, é importante ressaltar que as drogas, nas doses utilizadas neste estudo, não promoveram alteração da resposta motora, desde que não alteraram a atividade no teste do campo aberto, o que por si só, poderia alterar a resposta de IT. Assim, é possível que sugerir que o bloqueio específico de receptores CRF1 e CRF2 do BLA e do CeA promovem redução do medo e/ou da ansiedade, resultando em redução da resposta de IT em cobaias. / The tonic immobility response (TI ) occurs in inescapable situations of intense danger, such as the predator attack. This response is characterized by loss of righting reflex and the relative lack of responsiveness to environmental stimuli. Consistent studies have demonstrated the involvement of different brain areas to modulate this defensive behavior, including the periaqueductal gray matter, hypothalamus and amygdala. Whereas the amygdala in particular, studies have shown the involvement of receptors for corticotropin-releasing factor (CRF) of the central (CeA) and basolateral (BLA) nuclei os amygdala in TI modulating in guinea pigs. Indeed, in recent decades, several evidences suggest that CRF is closely correlated with emotional behavior associated with fear and anxiety. While it is clear the involvement of CRF receptors in the modulation of fear, and specifically in the modulation of TI, it is still unclear the involvement of different subtypes of CRF receptors in the emotional modulation. Thus, the aim of this study was to investigate the involvement of specific receptors for corticotropin-releasing factor, CRF1 and CRF2of BLA and of CeA in modulating the TI response in guinea pigs. To achieve these objectives, independent groups of guinea pigs were implanted with guide cannulae aimed for BLA or CeA were evaluated in the test of tonic immobility before and after the administration of specific antagonists of CRF1 receptors (CP- 376395) or CRF2 receptors (Astressin 2B), or after the administration of CRF preceded by CRF1or CRF2 antagonists, or CRF per se. In addition, to assess whether the drugs used altered locomotor activity, the open field test, for 5 minutes was performed after administration of antagonists for CRF1 receptors (CP- 376395) and CRF2 (Astressin 2B), at doses that alter the TI response in guinea pigs, and the CRF agonist preceded by CRF1 or CRF2. These results show that blockade of CRF1 and CRF2 receptors in the BLA and CeA reduced the duration of the defensive response of tonic immobility (TI) in guinea pigs. In contrast, activation of these receptors in the BLA and CeA increased the TI duration, demonstrated by administration of CRF in these amygdaloid regions. Also, specific antagonists for CRF1 and CRF2 receptors were able to block the increase in the TI response induced by CRF administered in the same structure. These results suggest that the effect promoted by CRF in the BLA and CeA is by joint performance of CRF1 and CRF2 receptors. Additionally, it is important to note that the drugs, in the doses used in this study, did not promote change in the motor response, since it did not alter the activity in the open field test, which by itself could alter the TI response. Thus, it is possible to suggest that the specific blockade of CRF1 and CRF2 receptors in the BLA and CeA promote reduction of fear and/or anxiety, resulting in reduced TI response in guinea pigs.

A resposta comportamental de Imobilidade Tônica (IT) ocorre em situações de perigo intenso, e em situações inescapáveis, como por exemplo,o ataque de um predador. Esta resposta caracteriza-se por perda do reflexo de endireitamento e relativa falta de responsividade aos estímulos ambientais. Estudos consistentes tem demonstrado o envolvimento de distintas áreas encefálicas na modulação desta resposta, entre elas a substância cinzenta periaquedutal, o hipotálamo e a amígdala. Considerando a amígdala em particular, estudos mostraram o envolvimento dos receptores para o fator liberador de corticotropina (CRF) dos núcleos basolateral (BLA) e central (CeA) na modulação da resposta de IT em cobaias. De fato, nas últimas décadas, várias evidências sugerem que o CRF está intimamente correlacionado com comportamento emocional associado ao medo e à ansiedade. Embora seja claro o envolvimento de receptores CRF na modulação do medo, e especificamente na modulação da IT em cobaias, ainda não está esclarecido o envolvimento dos diferentes subtipos de receptores para CRF na modulação emocional. Desta forma, o objetivo deste trabalho foi investigar o envolvimento dos receptores específicos para o fator liberador de corticotropina, CRF1 e CRF2 dos núcleos basolateral (BLA) e central da amígdala (CeA) na modulação da resposta de IT em cobaias.Para atingir estes objetivos, grupos independentes de cobaias, com implante de cânulas-guias dirigidas para o BLA ou para o CeA foram avaliadas no teste de imobilidade tônica, antes e depois da administração dos antagonistas específicos para receptores CRF1 (CP-376395) ou para receptores CRF2 (Astressin 2B), ou depois da administração de CRF precedido ou não dos antagonistas CRF1 ou CRF2. Em adição, para avaliar se as drogas utilizadas alteraram a atividade locomotora, foi realizado o teste do campo aberto, por 5 minutos, após a administração dos antagonistas para receptores CRF1 (CP-376395) e CRF2 (Astressin 2B), em doses capazes de alterar a resposta de IT em cobaias, e de CRF precedido por antagonista CRF1 ou CRF2. Os resultados deste trabalho mostram que o bloqueio dos receptores CRF1 e CRF2 no BLA e no CeA reduziram a duração da resposta defensiva de imobilidade tônica (IT) em cobaias. Inversamente, a ativação destes receptores no BLA e no CeA aumentou o tempo de IT, demonstrado pela administração de CRF nestas regiões amigdalóides. Ainda, os antagonistas específicos para receptores CRF1 e CRF2 foram capazes de bloquear o aumento da duração da IT induzida pelo CRF administrado no mesmo sítio. Estes resultados sugerem que o efeito promovido pelo CRF no BLA e no CeA ocorre por atuação conjunta em receptores CRF1 e CRF2. Em adição, é importante ressaltar que as drogas, nas doses utilizadas neste estudo, não promoveram alteração da resposta motora, desde que não alteraram a atividade no teste do campo aberto, o que por si só, poderia alterar a resposta de IT. Assim, é possível que sugerir que o bloqueio específico de receptores CRF1 e CRF2 do BLA e do CeA promovem redução do medo e/ou da ansiedade, resultando em redução da resposta de IT em cobaias. / The tonic immobility response (TI ) occurs in inescapable situations of intense danger, such as the predator attack. This response is characterized by loss of righting reflex and the relative lack of responsiveness to environmental stimuli. Consistent studies have demonstrated the involvement of different brain areas to modulate this defensive behavior, including the periaqueductal gray matter, hypothalamus and amygdala. Whereas the amygdala in particular, studies have shown the involvement of receptors for corticotropin-releasing factor (CRF) of the central (CeA) and basolateral (BLA) nuclei os amygdala in TI modulating in guinea pigs. Indeed, in recent decades, several evidences suggest that CRF is closely correlated with emotional behavior associated with fear and anxiety. While it is clear the involvement of CRF receptors in the modulation of fear, and specifically in the modulation of TI, it is still unclear the involvement of different subtypes of CRF receptors in the emotional modulation. Thus, the aim of this study was to investigate the involvement of specific receptors for corticotropin-releasing factor, CRF1 and CRF2of BLA and of CeA in modulating the TI response in guinea pigs. To achieve these objectives, independent groups of guinea pigs were implanted with guide cannulae aimed for BLA or CeA were evaluated in the test of tonic immobility before and after the administration of specific antagonists of CRF1 receptors (CP- 376395) or CRF2 receptors (Astressin 2B), or after the administration of CRF preceded by CRF1or CRF2 antagonists, or CRF per se. In addition, to assess whether the drugs used altered locomotor activity, the open field test, for 5 minutes was performed after administration of antagonists for CRF1 receptors (CP- 376395) and CRF2 (Astressin 2B), at doses that alter the TI response in guinea pigs, and the CRF agonist preceded by CRF1 or CRF2. These results show that blockade of CRF1 and CRF2 receptors in the BLA and CeA reduced the duration of the defensive response of tonic immobility (TI) in guinea pigs. In contrast, activation of these receptors in the BLA and CeA increased the TI duration, demonstrated by administration of CRF in these amygdaloid regions. Also, specific antagonists for CRF1 and CRF2 receptors were able to block the increase in the TI response induced by CRF administered in the same structure. These results suggest that the effect promoted by CRF in the BLA and CeA is by joint performance of CRF1 and CRF2 receptors. Additionally, it is important to note that the drugs, in the doses used in this study, did not promote change in the motor response, since it did not alter the activity in the open field test, which by itself could alter the TI response. Thus, it is possible to suggest that the specific blockade of CRF1 and CRF2 receptors in the BLA and CeA promote reduction of fear and/or anxiety, resulting in reduced TI response in guinea pigs.

Les travaux de cette thèse visent à étudier le role du système corticotropin-releasing factor (CRF) dans les dysfonctions cognitives, les altérations du comportement social et la vulnérabilité au stress associées à l’addiction aux drogues. Les effets de la délétion génétique du récepteur CRF1 ou CRF2 sont examinés dans les tests de reconnaissance d’objet et de préférence sociale après une exposition chronique et pendant le sevrage à la cocaine. Le rôle du récepteur CRF2 dans la vulnérabilité au stress qui pourrait précipiter l’apparition de déficits cognitifs et sociaux pendant le sevrage prolongé à la cocaine est également étudié. / Stimulant-related disorders are characterized by emotional-like, cognitive and social dysfunction that may contribute to the maintenance of the disease. In addition, stimulant use and withdrawal may alter brain stress systems. The corticotropin-releasing factor (CRF) system is a major stress coordinator hypothesized to contribute to substance-related disorders. CRF signalling is mediated by two receptor types, named CRF1 and CRF2. The specific role of each of the CRF receptors in negative affective-like, cognitive and social dysfunction associated with stimulant administration and withdrawal remains largely unknown. The present study demonstrates that the CRF1 receptor-deficiency increases the anxiety-like behaviour induced by intermittent administration of escalating doses of cocaine (5-20 mg/kg, i.p.), as assessed by the elevated plus maze. In addition, the same cocaine regimen induces novel object recognition (NOR) and sociability deficits, which are unaffected by CRF2 receptor-deficiency. However, CRF2 receptor-deficiency effectively shortens the duration of the NOR and sociability deficit induced by cocaine withdrawal. Furthermore, following the apparent recovery of NOR and sociability performances during relative long-term (42 days) cocaine withdrawal, CRF2 receptor-deficiency eliminates the stress-induced re-emergence of NOR and sociability deficit. Stressed cocaine-withdrawn mice show a genotype-independent higher c-fos mRNA expression in the perirhinal cortex, a brain region mediating NOR performance, than stressed drug-naïve mice. However, neither genotype nor drug withdrawal affects the expression of tyrosine hydroxylase in the ventral tegmentale area and the locus coeruleus, CRF in the amygdala and the paraventricular nucleus of the hypothalamus and dynorphin in the nucleus accumbens shell. The latter results suggest that stress vulnerability during long-term cocaine withdrawal is not due to alterations in stress-coping mechanisms. The present study provides initial evidence of a critical role for the CRF system in cognitive and sociability deficits and vulnerability induced by stimulant administration and withdrawal, suggesting new therapeutic strategies for substance-related disorders.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Parmi l’ensemble des désordres métaboliques retrouvés en insuffisance rénale chronique (IRC), la résistance à l’insuline demeure l’un des plus importantes à considérer en raison des risques de morbidité et de mortalité qu’elle engendre via les complications cardiovasculaires. Peu d’études ont considéré la modulation de transporteurs de glucose comme mécanisme sous-jacent à l’apparition et à la progression de la résistance à l’insuline en IRC. Nous avons exploré cette hypothèse en étudiant l’expression de transporteurs de glucose issus d’organes impliqués dans son homéostasie (muscles, tissus adipeux, foie et reins) via l’utilisation d’un modèle animal d’IRC (néphrectomie 5/6e). La sensibilité à l’insuline a été déterminée par un test de tolérance au glucose (GTT), où les résultats reflètent une intolérance au glucose et une hyperinsulinémie, et par les études de transport au niveau musculaire qui témoignent d’une diminution du métabolisme du glucose en IRC (~31%; p<0,05). La diminution significative du GLUT4 dans les tissus périphériques (~40%; p<0,001) peut être à l’origine de la résistance à l’insuline en IRC. De plus, l’augmentation de l’expression protéique de la majorité des transporteurs de glucose (SGLT1, SGLT2, GLUT1; p<0,05) au niveau rénal en IRC engendre une plus grande réabsorption de glucose dont l’hyperglycémie subséquente favorise une diminution du GLUT4 exacerbant ainsi la résistance à l’insuline. L’élévation des niveaux protéiques de GLUT1 et GLUT2 au niveau hépatique témoigne d’un défaut homéostatique du glucose en IRC. Les résultats jusqu’ici démontrent que la modulation de l’expression des transporteurs de glucose peut être à l’origine de la résistance à l’insuline en IRC. L’impact de la parathyroïdectomie (PTX) sur l’expression du GLUT4 a été étudié étant donné que la PTX pourrait corriger l’intolérance au glucose en IRC. Nos résultats démontrent une amélioration de l’intolérance au glucose pouvant être attribuable à la moins grande réduction de l’expression protéique du GLUT4 dans les tissus périphériques et ce malgré la présence d’IRC. L’excès de PTH, secondaire à l’hyperparathyroïdie, pourrait alors être à l’origine de la résistance à l’insuline en IRC en affectant l’expression du GLUT4. L’IRC partage de nombreuses similitudes avec le prédiabète quant aux défaillances du métabolisme du glucose tout comme l’hyperinsulinémie et l’intolérance au glucose. Aucune étude n’a tenté d’évaluer si l’IRC pouvait ultimement mener au diabète. Nos résultats ont par ailleurs démontré que l’induction d’une IRC sur un modèle animal prédisposé (rats Zucker) engendrait une accentuation de leur intolérance au glucose tel que constaté par les plus hautes glycémies atteintes lors du GTT. De plus, certains d’entre eux avaient des glycémies à jeun dont les valeurs surpassent les 25 mmol/L. Il est alors possible que l’IRC puisse mener au diabète via l’évolution de la résistance à l’insuline par l’aggravation de l’intolérance au glucose. / Of all metabolic disorders found in chronic renal failure (CRF), insulin resistance remains one of the most important to consider because of the risk of morbidity and mortality it causes via cardiovascular complications. Few studies have considered the modulation of glucose transporters as the mechanism underlying the emergence and progression of insulin resistance in CRF. We explored this hypothesis by studying the expression of glucose transporters from organs involved in its homeostasis (muscle , fat , liver and kidneys) through the use of an animal model reflecting CRF (5/6th nephrectomy). The insulin sensitivity was determined by a glucose tolerance test (GTT), where the results reflect glucose intolerance and hyperinsulinemia , and transport studies in muscle show a decrease in glucose uptake in CRF ratss (~31% , p<0.05). The significant decrease in GLUT4 in peripheral tissues (~40%, p<0.001) may be the cause of insulin resistance in CRF. Furthermore, increased protein expression of the majority of glucose transporters (SGLT1, SGLT2, GLUT1, p<0.05) within the kidney in CRF causes greater glucose reabsorption in which consequential hyperglycemia promotes a decrease in GLUT4 thus exacerbating insulin resistance. Elevated protein levels of GLUT1 and GLUT2 in the liver reflects an impaired glucose homeostasis in CRF. The results show that the modulation of the expression of glucose transporters may be responsible for insulin resistance in CRF. The impact of parathyroidectomy (PTX) on the expression of GLUT4 was studied since PTX is known to correct glucose intolerance in CRF. Our results show an improvement in glucose intolerance which may be due to less reduction of GLUT4 protein expression in peripheral tissues despite the presence of CRF. The excess of PTH, linked to secondary hyperparathyroidism, could be held responsible to the presence of insulin resistance in CRF by affectant GLUT4 expression. CRF shares many similarities with prediabetes in regards to impaired glucose metabolism such as hyperinsulinemia and glucose intolerance. No studies have attempted to assess whether CRF could lead to diabetes. Our results demonstrated that the induction of CRF in a predisposed animal model (Zucker rats) provoked greater glucose intolerance as evidenced by the highest blood glucose levels reached in the GTT. In addition, some of them had fasting blood glucose levels whose values exceeded 25 mmol/L. It is therefore possible that CRF can lead to diabetes through the evolution of insulin resistance by the worsening of glucose intolerance.