Os adenomas hipofisários podem ser tratados clinicamente com agonistas dopaminérgicos (AD) e/ou ligantes dos receptores de somatostatina (LRS). Alguns estudos apontam para o papel de polimorfismos dos genes DRD2, SSTR2 e SSTR5 na eficácia desses tratamentos clínicos. O objetivo do estudo foi avaliar o papel dos polimorfismos no gene DRD2 em pacientes com prolactinomas (n=118), corticotrofinomas (n=15), adenomas clinicamente não funcionantes (ACNF) (n=35) e somatotrofinomas (n=40), bem como de polimorfismos nos genes SSTR2 e SSTR5 em pacientes com somatotrofinomas (n=88), na resposta ao tratamento clínico com AD e LRS. Adicionalmente, comparar a frequência desses polimorfismos em pacientes portadores de adenomas hipofisários, de diferentes naturezas, a indivíduos saudáveis. Os polimorfismos foram genotipados por PCR em tempo real (sistema TaqMan) e seqüenciamento automático (método Sanger). Todos os genótipos estavam em equilíbrio de Hardy-Weinberg. Em nosso estudo, não houve correlação entre os polimorfismos de DRD2, SSTR2 e SSTR5 e a resposta ao tratamento clínico, com cabergolina (CAB) e/ou octreotida-LAR (OCT-LAR) respectivamente, em pacientes com prolactinomas, somatotrofinomas e corticotrofinomas. Nossos dados estão de acordo com estudos prévios em acromegálicos, no entanto não confirmaram associação de polimorfismo de DRD2 (rs6275) com resistência à CAB, anteriormente descrita em prolactinomas. Adicionalmente, os polimorfismos rs1800497 (alelo T) e rs1076560 (alelo A) de DRD2 foram correlacionados a macroadenomas, este último fator preditivo de resistência à CAB em prolactinomas. Quanto aos ACNF, nossos dados são inéditos e o polimorfismo rs6275 (alelo T) de DRD2 se correlacionou à progressão tumoral nos casos tratados com CAB. Comparando os adenomas hipofisários com indivíduos saudáveis, a presença do alelo raro A de rs1079597 de DRD2 foi inversamente associada à frequência de ACNF, enquanto que nos outros tipos tumorais não houve diferença. Em conclusão, os polimorfismos rs1079597 e rs6275 de DRD2 podem estar associados à tumorigênese e à resposta a CAB, no grupo ACNF respectivamente. Outros estudos ainda são necessários para definir o papel das variantes genéticas desses genes como um mecanismo envolvido na resistência aos AD e LRS e na tumorigênese hipofisária / Medical treatment of pituitary adenomas is mainly performed with dopamine agonist (DA) and/or somatostatin ligant receptor (SLR) drugs. In addition to dopamine receptor 2 (DRD2) and somatostatin receptors 2 and 5 (SSTR2 and SSTR5) tumor density, results of some studies pointed to the role of polymorphisms in the efficacy of clinical treatment. One of the goals of this study was to evaluate the association between DRD2 polymorphisms in patients with prolactinomas (n=118), corticotrophinomas (n=15), clinically nonfunctioning pituitary adenomas (CNFPA) (n=35) and somatotrophinoma (n=101) and polymorphisms in STTR2 and SSTR5, only in the last group; and response to treatment with DA and/or SLR. Another objective was to evaluate the frequency of polymorphisms in patients with different types of pituitary adenomas and compare them to healthy subjects. Polymorphisms were genotyped by real-time PCR (TaqMan system) and Sanger sequencing. All genotypes were in Hardy-Weinberg equilibrium. In patients with prolactinomas, somatotrophinomas and corticotrophinomas there was no association between genetic variants in DRD2 and response to treatment, like data in literature. However, an association between rs6275 (allele T) in DRD2 and CAB resistance in prolactinomas has been proposed. In addition, there was an association betweenrs1800497 (allele T) and rs1076560 (alelle A) in DRD2 and macroprolactinomas, this one predictive factor related to CAB resistance. The presence of rs6275 (allele T) in DRD2 was correlated with tumoral progression in CNFPA treated with CAB, never published previously. Comparing pituitary adenomas and health subjects, the presence of rs1079597 (allele A) was inversely associated with the frequency of CNFPA, otherwise there was no association for others pituitary adenomas. In conclusion, rs1079597 and rs6275 DRD2 polymorphisms might have an influence in tumorigenesis and CAB efficacy in patients with CNFPA, respectively. However, the results in the literature are conflicting and more studies are necessary to determine the role of these genetic variants like a mechanism involving in dopamine and somatostatin resistance and pituitary tumorigenesis

Dissertation (Ph.D.)--University of South Florida, 2008. / Title from PDF of title page. Document formatted into pages; contains 201 pages. Includes vita. Includes bibliographical references.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Este trabalho teve como objetivo investigar os efeitos da telmisartana (agonista PPAR-gama parcial), losartana (puro bloqueador do receptor AT1 da angiotensina II) e rosiglitazona (agonista PPAR-gama) em modelo experimental de síndrome metabólica. Os alvos do estudo foram a pressão arterial, metabolismo de carboidratos, resistência insulínica, inflamação, tecido adiposo e fígado. Camundongos C57BL/6 (a partir de 3 meses de idade) foram alimentados com dieta padrão (SC, n = 10) ou dieta hiperlipídica rica em sal (HFHS, n = 40) por 12 semanas. Após esse tempo, os animais do grupo HFHS foram subdivididos em 4 grupos (n = 10): HFHS (sem tratamento), ROSI (HFHS tratado com rosiglitazona), TELM (HFHS tratado com telmisartana) e LOS (HFHS tratado com losartana) por 5 semanas. O grupo HFHS apresentou um significante ganho de peso e aumento da pressão arterial sistólica, hiperinsulinemia com resistência insulínica, hiperleptinemia, hipertrofia de adipócitos bem como um quadro de esteatose hepática e níveis aumentados da citocina inflamatória interleucina-6 (IL-6). Os animais tratados com telmisartana chegou ao final do experimento com massa corporal similar ao grupo SC, com reversão do quadro de resistência insulínica, com pressão arterial normal, adipócitos de tamanho normal e sem apresentar esteatose hepática. Além disso, o tratamento com telmisartana aumentou a expressão de PPARγ e adiponectina no tecido adiposo epididimal. A expressão da proteína desacopladora-1 (UCP-1) no tecido adiposo branco (TAB) também foi aumentada. O tratamento com losartana diminuiu a pressão arterial para valores normais, porém com menores efeitos nos parâmetros metabólicos dos animais. O presente modelo experimental de ganho de peso e hipertensão induzidos por dieta mimetiza a síndrome metabólica humana. Neste modelo, a telmisartana aumentou a expressão de UCP-1 no TAB, preveniu o ganho de peso e melhorou a sensibilidade à insulina e a esteatose hepática dos camundongos C57BL/6, provavelmente devido à ativação PPAR-gama. / The study aimed to investigate the effects of telmisartan (a partial PPAR gamma agonist), losartan (a pure angiotensin II receptor blocker) and rosiglitazone (PPAR gamma agonist) in a mice model of metabolic syndrome (MetS). The targets of this study were blood pressure (BP), carbohydrate metabolism, insulin resistance, inflammation, white adipose tissue (WAT) and liver. Male C57BL/6 mice were studied over 17 weeks after being separated into two major groups according to diet: standard chow (SC, 10% fat, n = 10) or high-fat high-salt chow (HFHS, 60% fat, 7% salt, n = 40). In the last 5 weeks of the experiment, the HFHS group was divided into four groups (n = 10): untreated HFHS, ROSI (HFHS plus rosiglitazone), TELM (HFHS plus telmisartan), and LOS (HFHS plus losartan). The HFHS group had significantly greater body mass and BP, in addition to hyperinsulinemia with insulin resistance, hyperleptinemia, adipocyte hypertrophy and hepatic steatosis as well as increased inflammatory cytokine levels. Animals treated with telmisartan had body weights similar to the SC group, in addition to reversed insulin resistance, reduced hypertension, reduced adipocyte hypertrophy, ameliorates hepatic steatosis and decreased IL-6. Telmisartan increased PPARγ and adiponectin expression in white adipose tissue. Interestingly, the expression of UCP-1 in white adipose tissue was also increased by treatment with telmisartan. Losartan decreased BP but had smaller effects on metabolic parameters. The present model of diet-induced weight gain and hypertension in mice mimics human features of MetS. In this model, telmisartan enhances UCP-1 expression in WAT, prevented weight gain and ameliorates insulin sensitivity and hepatic steatosis in C57Bl/6 mice, probably due to PPAR gamma activation.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Este trabalho teve como objetivo investigar os efeitos da telmisartana (agonista PPAR-gama parcial), losartana (puro bloqueador do receptor AT1 da angiotensina II) e rosiglitazona (agonista PPAR-gama) em modelo experimental de síndrome metabólica. Os alvos do estudo foram a pressão arterial, metabolismo de carboidratos, resistência insulínica, inflamação, tecido adiposo e fígado. Camundongos C57BL/6 (a partir de 3 meses de idade) foram alimentados com dieta padrão (SC, n = 10) ou dieta hiperlipídica rica em sal (HFHS, n = 40) por 12 semanas. Após esse tempo, os animais do grupo HFHS foram subdivididos em 4 grupos (n = 10): HFHS (sem tratamento), ROSI (HFHS tratado com rosiglitazona), TELM (HFHS tratado com telmisartana) e LOS (HFHS tratado com losartana) por 5 semanas. O grupo HFHS apresentou um significante ganho de peso e aumento da pressão arterial sistólica, hiperinsulinemia com resistência insulínica, hiperleptinemia, hipertrofia de adipócitos bem como um quadro de esteatose hepática e níveis aumentados da citocina inflamatória interleucina-6 (IL-6). Os animais tratados com telmisartana chegou ao final do experimento com massa corporal similar ao grupo SC, com reversão do quadro de resistência insulínica, com pressão arterial normal, adipócitos de tamanho normal e sem apresentar esteatose hepática. Além disso, o tratamento com telmisartana aumentou a expressão de PPARγ e adiponectina no tecido adiposo epididimal. A expressão da proteína desacopladora-1 (UCP-1) no tecido adiposo branco (TAB) também foi aumentada. O tratamento com losartana diminuiu a pressão arterial para valores normais, porém com menores efeitos nos parâmetros metabólicos dos animais. O presente modelo experimental de ganho de peso e hipertensão induzidos por dieta mimetiza a síndrome metabólica humana. Neste modelo, a telmisartana aumentou a expressão de UCP-1 no TAB, preveniu o ganho de peso e melhorou a sensibilidade à insulina e a esteatose hepática dos camundongos C57BL/6, provavelmente devido à ativação PPAR-gama. / The study aimed to investigate the effects of telmisartan (a partial PPAR gamma agonist), losartan (a pure angiotensin II receptor blocker) and rosiglitazone (PPAR gamma agonist) in a mice model of metabolic syndrome (MetS). The targets of this study were blood pressure (BP), carbohydrate metabolism, insulin resistance, inflammation, white adipose tissue (WAT) and liver. Male C57BL/6 mice were studied over 17 weeks after being separated into two major groups according to diet: standard chow (SC, 10% fat, n = 10) or high-fat high-salt chow (HFHS, 60% fat, 7% salt, n = 40). In the last 5 weeks of the experiment, the HFHS group was divided into four groups (n = 10): untreated HFHS, ROSI (HFHS plus rosiglitazone), TELM (HFHS plus telmisartan), and LOS (HFHS plus losartan). The HFHS group had significantly greater body mass and BP, in addition to hyperinsulinemia with insulin resistance, hyperleptinemia, adipocyte hypertrophy and hepatic steatosis as well as increased inflammatory cytokine levels. Animals treated with telmisartan had body weights similar to the SC group, in addition to reversed insulin resistance, reduced hypertension, reduced adipocyte hypertrophy, ameliorates hepatic steatosis and decreased IL-6. Telmisartan increased PPARγ and adiponectin expression in white adipose tissue. Interestingly, the expression of UCP-1 in white adipose tissue was also increased by treatment with telmisartan. Losartan decreased BP but had smaller effects on metabolic parameters. The present model of diet-induced weight gain and hypertension in mice mimics human features of MetS. In this model, telmisartan enhances UCP-1 expression in WAT, prevented weight gain and ameliorates insulin sensitivity and hepatic steatosis in C57Bl/6 mice, probably due to PPAR gamma activation.

Os adenomas hipofisários podem ser tratados clinicamente com agonistas dopaminérgicos (AD) e/ou ligantes dos receptores de somatostatina (LRS). Alguns estudos apontam para o papel de polimorfismos dos genes DRD2, SSTR2 e SSTR5 na eficácia desses tratamentos clínicos. O objetivo do estudo foi avaliar o papel dos polimorfismos no gene DRD2 em pacientes com prolactinomas (n=118), corticotrofinomas (n=15), adenomas clinicamente não funcionantes (ACNF) (n=35) e somatotrofinomas (n=40), bem como de polimorfismos nos genes SSTR2 e SSTR5 em pacientes com somatotrofinomas (n=88), na resposta ao tratamento clínico com AD e LRS. Adicionalmente, comparar a frequência desses polimorfismos em pacientes portadores de adenomas hipofisários, de diferentes naturezas, a indivíduos saudáveis. Os polimorfismos foram genotipados por PCR em tempo real (sistema TaqMan) e seqüenciamento automático (método Sanger). Todos os genótipos estavam em equilíbrio de Hardy-Weinberg. Em nosso estudo, não houve correlação entre os polimorfismos de DRD2, SSTR2 e SSTR5 e a resposta ao tratamento clínico, com cabergolina (CAB) e/ou octreotida-LAR (OCT-LAR) respectivamente, em pacientes com prolactinomas, somatotrofinomas e corticotrofinomas. Nossos dados estão de acordo com estudos prévios em acromegálicos, no entanto não confirmaram associação de polimorfismo de DRD2 (rs6275) com resistência à CAB, anteriormente descrita em prolactinomas. Adicionalmente, os polimorfismos rs1800497 (alelo T) e rs1076560 (alelo A) de DRD2 foram correlacionados a macroadenomas, este último fator preditivo de resistência à CAB em prolactinomas. Quanto aos ACNF, nossos dados são inéditos e o polimorfismo rs6275 (alelo T) de DRD2 se correlacionou à progressão tumoral nos casos tratados com CAB. Comparando os adenomas hipofisários com indivíduos saudáveis, a presença do alelo raro A de rs1079597 de DRD2 foi inversamente associada à frequência de ACNF, enquanto que nos outros tipos tumorais não houve diferença. Em conclusão, os polimorfismos rs1079597 e rs6275 de DRD2 podem estar associados à tumorigênese e à resposta a CAB, no grupo ACNF respectivamente. Outros estudos ainda são necessários para definir o papel das variantes genéticas desses genes como um mecanismo envolvido na resistência aos AD e LRS e na tumorigênese hipofisária / Medical treatment of pituitary adenomas is mainly performed with dopamine agonist (DA) and/or somatostatin ligant receptor (SLR) drugs. In addition to dopamine receptor 2 (DRD2) and somatostatin receptors 2 and 5 (SSTR2 and SSTR5) tumor density, results of some studies pointed to the role of polymorphisms in the efficacy of clinical treatment. One of the goals of this study was to evaluate the association between DRD2 polymorphisms in patients with prolactinomas (n=118), corticotrophinomas (n=15), clinically nonfunctioning pituitary adenomas (CNFPA) (n=35) and somatotrophinoma (n=101) and polymorphisms in STTR2 and SSTR5, only in the last group; and response to treatment with DA and/or SLR. Another objective was to evaluate the frequency of polymorphisms in patients with different types of pituitary adenomas and compare them to healthy subjects. Polymorphisms were genotyped by real-time PCR (TaqMan system) and Sanger sequencing. All genotypes were in Hardy-Weinberg equilibrium. In patients with prolactinomas, somatotrophinomas and corticotrophinomas there was no association between genetic variants in DRD2 and response to treatment, like data in literature. However, an association between rs6275 (allele T) in DRD2 and CAB resistance in prolactinomas has been proposed. In addition, there was an association betweenrs1800497 (allele T) and rs1076560 (alelle A) in DRD2 and macroprolactinomas, this one predictive factor related to CAB resistance. The presence of rs6275 (allele T) in DRD2 was correlated with tumoral progression in CNFPA treated with CAB, never published previously. Comparing pituitary adenomas and health subjects, the presence of rs1079597 (allele A) was inversely associated with the frequency of CNFPA, otherwise there was no association for others pituitary adenomas. In conclusion, rs1079597 and rs6275 DRD2 polymorphisms might have an influence in tumorigenesis and CAB efficacy in patients with CNFPA, respectively. However, the results in the literature are conflicting and more studies are necessary to determine the role of these genetic variants like a mechanism involving in dopamine and somatostatin resistance and pituitary tumorigenesis

Die niedrige Inzidenz chronisch-entzündlicher Darmerkrankungen (CED) in ostasiatischen Ländern im Vergleich zu Westeuropa und den USA könnte auf unterschiedliche Lebensstile und Ernährungsgewohnheiten zurückzuführen sein. Asiaten nehmen mit der Nahrung viel höhere Mengen an Isoflavonen zu sich als Europäer und US-Amerikaner. Diese sind in der Lage, wie natürliche Östrogene an Östrogenrezeptoren (ER) zu binden. Für das Östrogen 17β-Östradiol (E2) sowie selektive Liganden des ERβ sind antiinflammatorische Wirkungen im Darm bereits nachgewiesen worden. Diese Arbeit untersuchte in Modellsystemen für CED die antiinflammatorischen Eigenschaften von Isoflavonen, speziell von Genistein, und stellte einen Vergleich mit synthetischen ER-selektiven Liganden sowie E2 her, um die Involvierung der beiden ER-Subtypen zu evaluieren. In tierexperimentellen Studien wurde der Einfluss der Testsubstanzen auf Ausprägung und Verlauf einer Kolitis in zwei Nagermodellen (HLA-B27 transgene Ratte und TNBS-induzierte Kolitis) analysiert. Ein Ernährungsexperiment, in dem eine Gruppe der Tiere bereits in utero sowie postnatal über Muttermilch und Futter hohen Phytoöstrogenspiegeln ausgesetzt war, zeigte wider Erwarten keine antiinflammatorischen Effekte auf die akute Ausprägung der induzierten Kolitis. Stattdessen waren die untersuchten Parameter bei dieser Ernährungsform gegenüber prä- und postnatal normal ernährten Tieren verstärkt. Dagegen bewirkte oral verabreichtes Genistein in der chronischen Phase der TNBS-induzierten Kolitis eine Unterdrückung der Entzündungsparameter im Darm. Die subkutane Verabreichung von Genistein, eines steroidalen ERβ-selektiven Agonisten, oder von E2 führte hingegen zu keiner signifikanten Einflussnahme auf die untersuchten Parameter in der akuten Phase der Inflammation. Zur Charakterisierung der molekularen Grundlagen einer antiinflammatorischen Wirkung von E2, synthetischen ER-selektiven Agonisten und Genistein wurden in vitro Studien mit Kolonkarzinomzelllinien (HT-29 und Caco-2) durchgeführt. Hierzu wurden die Zellen mit Interleukin-1β (IL-1β) stimuliert, was eine Induktion der inflammationsassoziierten Gene Cyclooxygenase-2 und Interleukin-6 auf mRNA Ebene bewirkte. Bis auf Genistein konnten für die getesteten Substanzen keine antiinflammatorischen Effekte auf die mRNA-Expression der induzierten Markergene beobachtet werden. Genistein bewirkte in Caco-2 Zellen eine Hemmung der untersuchten Gene. Weitere Analysen ergaben, dass die beiden Zelllinien ER nur schwach bzw. gar nicht exprimieren. Eine Transfektion von HT-29 Zellen mit ERα führte zu einer deutlichen Hemmung der Expression der Markergene durch E2, während eine Transfektion mit ERβ lediglich einen schwach hemmenden Effekt bewirkte. Die Ergebnisse der vorliegenden Arbeit legen nahe, dass die niedrigen CED-Inzidenzraten in Ostasien wohl nicht allein auf dem dortigen hohen Isoflavonkonsum beruhen, sondern auch anderen Komponenten des Lebensstils zuzuschreiben sind. Dennoch deutet sich an, dass das Genistein, bei oraler Administration, die Regeneration des geschädigten Darmgewebes im chronischen Erkrankungsverlauf unterstützen und damit auch zur Prävention von Kolonkarzinomen beitragen könnte. Bei antiinflammatorischen Effekten von ER-Liganden spielt die Transaktivierung von ER eine entscheidende Rolle. Die Wirkung von Genistein in untransfizierten Caco-2 Zellen legt jedoch auch die Teilnahme weiterer Mechanismen nahe, die noch zu untersuchen sind. Vor diesem Hintergrund erscheinen weiterführende Untersuchungen zum Einsatz von steroidalen ER-Agonisten und Genistein bei CED und den zugrunde liegenden Mechanismen als sinnvoll.

Indiana University-Purdue University Indianapolis (IUPUI) / It has been proposed that the GABAB receptor subtype plays a role in alcoholism and alcohol use disorders (AUDs) (Cousins et al., 2002; Agabio et al., 2012). Specifically, the GABAB agonist baclofen has been looked at extensively in clinical and pre-clinical studies. In various animal models of chronic and intermittent consumption, baclofen has been shown to both increase (Petry, 1997; Smith et al., 1999; Czachowski et al., 2006; Moore et al., 2007) and decrease (Colombo et al., 2000; 2002; 2005; Stromberg, 2004; Moore et al., 2009) drinking. A critical issue in determining pharmacological effects of a drug is using the appropriate animal model. The drinking-in-the-dark (DID) model, developed by Rhodes et al. (2005, 2007), produces high levels of drinking in a binge-like paradigm and has been used to assess many pharmacological targets (e.g. Kamdar et al., 2007; Gupta et al., 2008; Moore et al., 2007; 2009). While DID produces high-levels of binge drinking, it is unclear what areas of the brain are involved in this behavior. A direct way to target areas that are believed to be involved in the circuitry of particular behaviors is through microinjection of drugs (Kiianmaa et al., 2003). Of particular recent interest involving motivated behaviors and addiction is the nucleus accumbens (Acb) (Everitt & Robbins, 2005); specifically the accumbens shell (AcbSh) (e.g. Rewal et al., 2009, 2012; Nie et al., 2011; Leriche et al., 2008). The current study aimed to investigate the role of GABAB receptors in the AcbSh by examining the ability of two different enantiomers of baclofen to alter ethanol and saccharin intake in male C57BL/6J (B6) mice. B6 mice underwent bilateral cannulation surgery targeting the AcbSh. After 48 hours of recovery time, animals began a five day Drinking-in-the-Dark (DID) procedure where they received 20% ethanol or 0.2% saccharin for two hours, three hours into the dark cycle, each day. Throughout the five drinking sessions, animals were kept in home-cage locomotor activity chambers to monitor activity throughout the drinking cycle. Day 4 drinking was immediately preceded by a mock microinjection, whereas Day 5 drinking was immediately preceded by a drug microinjection. Microinjection of one of five doses of baclofen was given in ng/side dissolved in 200 µl of aCSF (aCSF alone, 0.02 R(+)-, 0.04 R(+)-, 0.08 S(-)-, or 0,16 S(-)-). Intake was recorded every twenty minutes on Days 4 and 5. Retro-orbital sinus blood samples were taken from ethanol animals immediately following the Day 5 drinking period to determine blood ethanol concentrations (BECs). A one-way ANOVA on total Day 4 ethanol consumption revealed no baseline differences between dose groups. A one-way ANOVA on total Day 5 ethanol consumption revealed that the 0.04 R(+)- baclofen dose reduced total drinking, but the 0.16 S(-)- baclofen dose increased total drinking (p’s<0.05). This pattern was reflected in the BECs; 0.04 R(+)- baclofen reduced BECs, whereas 0.16 S(-)- baclofen increased BECs (p’s<0.05). These results were also time-dependent, with R(+)-baclofen reducing drinking in the first 20 minutes of the session and S(-)- increasing drinking in the last 40 minutes of the session. There were no effects on saccharin intake. An issue with the locomotor activity boxes led to unreliable locomotor activity counts. However, because there were no drug effects on saccharin consumption, it was concluded that locomotor effects did not contribute to the decreases or increases in ethanol consumption. These results further implicate the role of GABAB receptors in modulating ethanol intake. The bidirectional effects shown highlight the importance of considering enantioselective drug effects when interpreting data. Finally, these results also support previous conclusions that the AcbSh plays an important role in modulating use of drugs of abuse, but not other reinforcers.

OBJECTIVE: Human myometrium contains both beta1-adrenergic and beta2-adrenergic receptors. This study was designed to assess the importance of each beta-adrenergic receptor subtype in relaxation of human myometrial muscle strips. STUDY DESIGN: Radioligand binding studies were used to establish the presence of each beta-adrenergic receptor subtype, whereas highly selective beta1-antagonists and beta2-antagonists were used to assess the contribution of beta-adrenergic receptor subtypes to myometrial relaxation after exposure to (-)-isoproterenol. RESULTS: Membranes prepared from myometrium contained 82% +/- 4% beta2-adrenergic receptors. After contraction produced by exposure to potassium chloride (35 mmol/L), isoproterenol produced relaxation with half maximal effect at 0.02 micromol/L and a maximal relaxation of 52% +/- 3%. Beta1-antagonist CGP-20712A had no significant effect, whereas beta2-antagonist ICI-118551 produced a characteristic rightward shift of the isoproterenol concentration-relaxation relationship. CONCLUSIONS: Although both beta1-adrenergic receptors and beta2-adrenergic receptors are present in human myometrial tissue at term, relaxation by nonselective beta-agonist isoproterenol is mediated exclusively by beta2-adrenergic receptors.

No / The alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor (AMPAR) subunit GluR2, which regulates excitotoxicity and the inflammatory cytokine tumour necrosis factor alpha (TNFalpha) have both been implicated in motor neurone vulnerability in amyotrophic lateral sclerosis/motor neurone disease. TNFalpha has been reported to increase cell surface expression of AMPAR subunits to increase synaptic strength and enhance excitotoxicity, but whether this mechanism occurs in motor neurones is unknown. We used primary cultures of mouse motor neurones and cortical neurones to examine the interaction between TNFalpha receptor activation, GluR2 availability, AMPAR-mediated calcium entry and susceptibility to excitotoxicity. Short exposure to a physiologically relevant concentration of TNFalpha (10 ng/mL, 15 min) caused a marked redistribution of both GluR1 and GluR2 to the cell surface as determined by cell surface biotinylation and immunofluorescence. Using fura-2-acetoxymethyl ester microfluorimetry, we showed that exposure to TNFalpha caused a rapid reduction in the peak amplitude of AMPA-mediated calcium entry in a PI3-kinase and p38 kinase-dependent manner, consistent with increased insertion of GluR2-containing AMPAR into the plasma membrane. This resulted in a protection of motor neurones against kainate-induced cell death. Our data therefore, suggest that TNFalpha acts primarily as a physiological regulator of synaptic activity in motor neurones rather than a pathological drive in amyotrophic lateral sclerosis.

Introdução: O gene TCF7L2 (Transcription Factor 7-Like 2) codifica o fator de transcrição de mesmo nome que, tem importante papel na via Wnt de sinalização intra celular. A via Wnt é constituída por proteínas de integração e ligação dos processos de diferenciação e multiplicação celulares, interagindo com os fatores TCF, e ativando a expressão de genes relacionados ao TCF7L2, sendo este amplamente expresso em vários tecidos. Dados epidemiológicos atuais não deixam dúvidas quanto à forte associação de polimorfismos do gene TCF7L2 com o diabetes tipo 2 (DM2) em diferentes etnias. Apesar de serem pouco conhecidos os mecanismos que envolvem o gene TCF7L2 no DM2, tem sido bem demonstrada a associação do alelo T no rs7903146 com redução da secreção de insulina, redução do efeito das incretinas, principalmente do GLP-1, aumento na secreção de glucagon e a longo prazo, redução da meia vida da célula beta. Em vista destas evidências, aventamos a hipótese de que pacientes com DM2 portadores da variante rs7903146 do gene TCF7L2, ao ser tratados com GLP-1 mimético, poderiam responder de forma peculiar. Objetivos: Avaliar a resposta hormonal pancreática antes e após tratamento com GLP-1 mimético em indivíduos com DM2 portadores da variante rs7903146 do gene TCF7L2. Pacientes e Métodos: Foram genotipados162 indivíduos com DM2 portadores da variante rs7903146 do gene TCF7L2: idade (57,0 &#177; 7,6) anos, IMC (30,5 &#177; 5,1) kg/m2. Dessa amostra, 56 pacientes foram divididos em dois grupos conforme o genótipo, sendo 26 CC x 30 CT/TT, e a seguir tratados com Exenatide durante oito semanas. Os testes de refeição foram realizados antes e após o tratamento, para avaliação das concentrações plasmáticas de: Glicose (mg/dl), Insulina (&#956;U/dl), Pró-insulina (pmol/L), Peptideo-c (ng/ml); Glucagon (pg/ml) e GLP-1(pmol/L). Foram comparadas as áreas sob as curvas e os pontos das curvas durante o teste. Análise estatística por ANOVA com dois fatores e medidas repetidas, nível de significância maior que 5%. Resultados: A distribuição genotípica CC x CT x TT foi 41,4% x 47,5% x 11,1% respectivamente. A influência do alelo T na resposta pancreática durante o teste da refeição mostrou que as concentrações plasmáticas de insulina, pró-insulina e peptídeo-c foram maiores no grupo CT/TT do que no CC (p<0,05) mas, não houve diferença na secreção do glucagon, GLP-1 e na glicemia entre os grupos (NS).Com relação à influência do alelo T na resposta ao tratamento verificou-se que o grupo CT/TT apresentou maior redução da secreção de insulina (p<0,005), peptídeo-c (p<0,05) e pró-insulina (p<0,001) do que o grupo CC durante o teste da refeição após o tratamento. Observou-se diminuição da glicemia, do glucagon e do GLP-1 de forma semelhante em ambos os grupos. Além disso, houve diminuição semelhante do peso e da hemoglobina glicosilada em ambos os grupos. Discussão: Os resultados do presente estudo mostraram que a presença do alelo T em indivíduos com DM2 esteve associada à maior secreção de insulina, pró-insulina e peptídeo-c em relação aos não portadores, com semelhantes concentrações séricas de glucagon e glicose em resposta ao teste da refeição. Este dado demonstra que a função da célula &#946; dos portadores da variante rs7903146 apresenta características diferentes dos não portadores. Após o tratamento com Exenatide, os indivíduos com DM2 e genótipo CT/TT, apresentaram valores estatisticamente menores de insulina, pró-insulina e peptídeo-c do que o grupo CC. Os efeitos do GLP-1 na glicemia pós-prandial são atribuídos a mecanismos de supressão do glucagon, lentificação do esvaziamento gástrico e também a efeitos insulinotrópicos e decorrentes de aumento na sensibilidade periférica à insulina. Além disso, já foi demonstrado que o Exenatide aumenta a captação de glicose de forma insulino-independente em músculo esquelético, pelo estímulo dos transportadores de glicose. Portanto, acredita-se que as características da resposta observada após o tratamento nos portadores do alelo T correspondem ao efeito do Exenatide na célula &#946; melhorando o processamento da pró-insulina, peptídeo-c e insulina e ao aumento da captação periférica da glicose. Sugere-se que esse processo seja resultante da melhor interação com os receptores de GLP-1, tanto em fígado, músculo esquelético e pâncreas. Conclusões: Os dados sugerem que indivíduos com DM2 portadores do alelo T no rs7903146 do gene TCF7L2 apresentam mais benefícios do tratamento com Exenatide, pois a secreção de insulina, pró-insulina e peptídeo-c foram condizentes com maior qualidade na função de célula &#946; nesse grupo após o tratamento. Além disso, o presente estudo proporcionou adicionais evidências clínicas de que os problemas que associam o TCF7L2 ao DM2 estão relacionados à tolerância periférica a glicose. / Introduction:The TCF7L2 gene (Transcription Factor 7-Like 2) encodes the transcription factor of the same name that has an important role in the intracellular Wnt signaling. The Wnt pathway is composed of connecting and integrating proteins of cell proliferation and differentiation process by interacting with TCF factors, and activating the expression of genes related to TCF7L2, which is widely expressed in several tissues. Current epidemiological data leave no doubt as to the strong association of polymorphisms of the TCF7L2 gene with type 2 diabetes (T2DM) in different ethnic groups. Although they are poorly known mechanisms involving TCF7L2 gene in DM2 the association of the T allele of rs7903146 with reduced insulin secretion, reducing effect of incretins, mainly GLP-1, increase in glucagon secretion and long-term reduction in the half-life of the beta cell, have been well demonstrated. In view of this evidences, we hypothesized that patients with DM2 carriers of the variant rs7903146 of the TCF7L2 gene, being treated with GLP-1 mimetic, could respond in a peculiar way. Objectives: Evaluating the pancreatic hormone response before and after treatment with GLP-1 mimetic in individuals with T2DM carriers of rs7903146 variant of TCF7L2 gene. Patients and Methods: We genotyped 162 individuals with T2DM patients with the variant rs7903146 gene TCF7L2: age ( 57.0 &#177; 7.6 ) years old, BMI ( 30.5 &#177; 5.1 ) kg/m2. From this sample, 56 patients were divided into two groups according to the genotype, 26 x 30 CC CT / TT, and then treated with exenatide for eight weeks. Meal tests were conducted before and after treatment to evaluate plasma concentrations of: Glucose ( mg / dl) Insulin ( U / dL ) Proinsulin (pmol / L), C-peptide (ng / ml) , Glucagon (pg / ml) and GLP-1 (pmol / L). The areas under the curves and the points of the curves were compared during the test. Statistical analysis by ANOVA with two factors and repeated measures, significance level greater than 5%. Results: The genotype distribution CC x CT x TT was 41.4% vs. 47.5% vs. 11.1 % respectively. The influence of the T allele in the pancreatic response during the test meal showed that plasma insulin concentrations, pro-insulin and c-peptide were higher in the CT / TT than in CC (p <0.05) but no difference in the glucagon secretion, GLP-1 and glucose in both groups (NS). Regarding to the influence of the T allele in response to treatment has been found that the group CT / TT presented greater reduction in insulin secretion (p <0.005) c-peptide (p <0.05) and proinsulin (p <0.001) than in CC group during the test meal after treatment. There was a decrease in blood glucose, glucagon and GLP-1 similarly in both groups. In addition, there was a similar decrease in weight and glycosylated hemoglobin in both groups. Discussion: The results of this study showed that the presence of the T allele in individuals with T2DM was associated with higher insulin secretion, proinsulin and c-peptide compared to non-carriers, with similar serum concentrations of glucagon and glucose in response to the test meal. This data demonstrates that the function of &#946; cells of carriers of the variant rs7903146 shows different features from non-carriers. After treatment with Exenatide, individuals with T2DM and genotype CT / TT, showed statistically lower values of insulin, proinsulin and c-peptide than the CC group. The effects of GLP-1 on postprandial glycemia mechanisms are attributed to suppression of glucagon, retardation of gastric emptying and also the insulinotropic effects and resulting increase in peripheral sensitivity to insulina. In addition, it was demonstrated that the Exenatide increases glucose uptake independent of insulin in skeletal muscle, the stimulation of glucose transporters way. Therefore, it is believed that the characteristics of the response observed after treatment in patients with the T allele corresponds to the effect of Exenatide in &#946; cell improving the processing of proinsulin, insulin and c-peptide and increasing peripheral glucose uptake. It is suggested that this process is best resulting from the interaction with the GLP-1 receptor in both liver, skeletal muscle and pancreas. Conclusions: These data suggest that individuals with T2DM patients with T allele in rs7903146 of TCF7L2 presents more benefits of treatment with Exenatide, because the secretion of insulin, proinsulin and c-peptide were consistent with higher quality in &#946; cell function in that group after treatment. Moreover, this study provided further evidence that the clinical problems associated with T2DM and TCF7L2 are related to peripheral glucose tolerance.