Diabetes Mellitus is a group of diseases, prevalence and incidence of which is on the rise not only in the Czech Republic, but also worldwide. This diploma work aims to analyze market situation and opportunities for modern oral anti-diabetic drugs. This work also designs suitable positioning for new OADs of Novartis -- Galvus and Eucreas.

O aumento nos casos de obesidade em todo o mundo tem gerado grande preocupação e estimulado pesquisas na prevenção e tratamento dessa condição patológica. A combinação de diabetes tipo 2 ou resistência insulínica com obesidade agrava o potencial evolutivo da enfermidade. Mesmo pacientes submetidos com sucesso à cirurgia bariátrica ou metabólica, podem não se curar do diabetes, pois a melhora das taxas circulantes de glicose e insulina nem sempre corresponde à recuperação da massa beta pancreática. Até o momento, não há consenso sobre como medir a massa de células beta in vivo. As ferramentas disponíveis padecem de baixa sensibilidade e especificidade, muitas vezes revelando-se também complexas e dispendiosas. Incretinas radiomarcadas ,como os análogos do peptídeo glucagon-like-peptide-1 / GLP-1, têm-se revelado promissoras para avaliação de células beta pancreáticas, em diabetes e insulinoma. O objetivo do presente trabalho foi o desenvolvimento de dois conjugados de análogo de incretina GLP-1, marcados com tecnécio-99m, a fim de propor um método não invasivo de imagem, para monitoração da massa de células beta pancreáticas, em organismos afetados por obesidade. O estudo foi conduzido em diferentes modelos animais, incluindo obesidade induzida por dieta hiperlipídica, estado pós-obesidade em que o distúrbio inicialmente gerado foi parcialmente corrigido, e como controle, diabetes induzido com aloxana. Nos resultados, os radiotraçadores alcançaram um rendimento radioquímico superior a 97%. O melhor radiomarcador, dentre os dois análogos ensaiados, foi o 99mTc-HYNIC-βAla-Exendin-4. Animais com obesidade induzida por dieta revelaram captação reduzida nas células beta pancreáticas. A restrição dietética (estado pós-obesidade) não se seguiu de recuperação completa, embora notável melhora de glicemia haja sido observada. Estudos futuros são indicados em modelos de obesidade, diabetes tipo 2 e tratamento dietético, incluindo cirurgia bariátrica e metabólica. / Increased prevalence of obesity worldwide, has become a vast concern, stimulating investigations focusing prevention and therapy of this condition. The association of type 2 diabetes or insulin resistance aggravates the prognosis of obesity. Even patients successfully submitted to bariatric or metabolic surgery, may not be cured of diabetes, as improvement of circulating values of glucose and insulin not necessarily reflects recovery of pancreatic beta cell mass. There is no consensus about how to estimate beta cell mass in vivo. Available tools suffer from low sensitivity and specificity, often being as well cumbersome and expensive. Radiolabeled incretins, such as glucagon-like-peptide 1 (GLP-1) analogs, seem to be promising options for the measurement of beta cell mass in diabetes and insulinoma. The objective of this study was the development of two conjugates of GLP-1 analog, radiolabeled with 99m Technetium, as a noninvasive imaging method for the estimation of pancreatic beta cell mass, in the presence of obesity. Animal models were selected, including hyperlipidic diet-induced obesity, diet restricted obesity, and as controls, alloxan diabetes. Results indicated that both radiotracers achieved over 97% radiochemical yield. The most successful product was 99mTc-HYNIC-βAla-Exendin-4. Low beta cell mass uptake occurred in diet-induced obesity. Diet-restricted obesity, with substantial shedding of excess body weight, was followed by remarkable decrease of fasting blood glucose, however beta cell mass uptake was only mildly improved. Future studies are recommended in obesity, type 2 diabetes, and dieting, including bariatric and metabolic operations.

O aumento nos casos de obesidade em todo o mundo tem gerado grande preocupação e estimulado pesquisas na prevenção e tratamento dessa condição patológica. A combinação de diabetes tipo 2 ou resistência insulínica com obesidade agrava o potencial evolutivo da enfermidade. Mesmo pacientes submetidos com sucesso à cirurgia bariátrica ou metabólica, podem não se curar do diabetes, pois a melhora das taxas circulantes de glicose e insulina nem sempre corresponde à recuperação da massa beta pancreática. Até o momento, não há consenso sobre como medir a massa de células beta in vivo. As ferramentas disponíveis padecem de baixa sensibilidade e especificidade, muitas vezes revelando-se também complexas e dispendiosas. Incretinas radiomarcadas ,como os análogos do peptídeo glucagon-like-peptide-1 / GLP-1, têm-se revelado promissoras para avaliação de células beta pancreáticas, em diabetes e insulinoma. O objetivo do presente trabalho foi o desenvolvimento de dois conjugados de análogo de incretina GLP-1, marcados com tecnécio-99m, a fim de propor um método não invasivo de imagem, para monitoração da massa de células beta pancreáticas, em organismos afetados por obesidade. O estudo foi conduzido em diferentes modelos animais, incluindo obesidade induzida por dieta hiperlipídica, estado pós-obesidade em que o distúrbio inicialmente gerado foi parcialmente corrigido, e como controle, diabetes induzido com aloxana. Nos resultados, os radiotraçadores alcançaram um rendimento radioquímico superior a 97%. O melhor radiomarcador, dentre os dois análogos ensaiados, foi o 99mTc-HYNIC-βAla-Exendin-4. Animais com obesidade induzida por dieta revelaram captação reduzida nas células beta pancreáticas. A restrição dietética (estado pós-obesidade) não se seguiu de recuperação completa, embora notável melhora de glicemia haja sido observada. Estudos futuros são indicados em modelos de obesidade, diabetes tipo 2 e tratamento dietético, incluindo cirurgia bariátrica e metabólica. / Increased prevalence of obesity worldwide, has become a vast concern, stimulating investigations focusing prevention and therapy of this condition. The association of type 2 diabetes or insulin resistance aggravates the prognosis of obesity. Even patients successfully submitted to bariatric or metabolic surgery, may not be cured of diabetes, as improvement of circulating values of glucose and insulin not necessarily reflects recovery of pancreatic beta cell mass. There is no consensus about how to estimate beta cell mass in vivo. Available tools suffer from low sensitivity and specificity, often being as well cumbersome and expensive. Radiolabeled incretins, such as glucagon-like-peptide 1 (GLP-1) analogs, seem to be promising options for the measurement of beta cell mass in diabetes and insulinoma. The objective of this study was the development of two conjugates of GLP-1 analog, radiolabeled with 99m Technetium, as a noninvasive imaging method for the estimation of pancreatic beta cell mass, in the presence of obesity. Animal models were selected, including hyperlipidic diet-induced obesity, diet restricted obesity, and as controls, alloxan diabetes. Results indicated that both radiotracers achieved over 97% radiochemical yield. The most successful product was 99mTc-HYNIC-βAla-Exendin-4. Low beta cell mass uptake occurred in diet-induced obesity. Diet-restricted obesity, with substantial shedding of excess body weight, was followed by remarkable decrease of fasting blood glucose, however beta cell mass uptake was only mildly improved. Future studies are recommended in obesity, type 2 diabetes, and dieting, including bariatric and metabolic operations.

No description available.

Les lipopolysaccharides sont des molécules présentes à la surface des bactéries Gram(-). Dans certaines situations, ces molécules se retrouvent dans la circulation sanguine et induisent une réponse inflammatoire. Quelle que soit l’intensité de la réponse initiée par les LPS, de profondes perturbations métaboliques vont avoir lieu. Le métabolisme glucidique est particulièrement affecté. Chez l’homme, en cas d’infection sévère, telle que le sepsis, le contrôle strict de l’hyperglycémie induite par les LPS via une insulinothérapie est le sujet d’actives recherches de la communauté scientifique et médicale. Par ailleurs, ces dernières années, est apparue la notion d’endotoxémie métabolique, réliée en partie à des régimes alimentaires riches en graisses. Les LPS seraient l’un des nombreux facteurs impliqués dans l’étiologie des maladies métaboliques. Dans ce contexte, nous avons étudié la réponse de l’organisme au glucose dans le cas d’endotoxémie expérimentale contrôlée. Exclusivement basée sur l’étude de différents modèles animaux, notre approche expérimentale a permis de montrer que l’administration aigüe ou continue de LPS, induisait une augmentation de la sécrétion d’insuline stimulée par le glucose ainsi qu’une augmentation de la clairance du glucose. Enfin, cette augmentation de sécrétion d’insuline était due à une augmentation des taux circulants de glucagon like peptide-1(GLP-1) et que le récepteur au GLP-1 était impliqué dans cette réponse. Elucider les mécanismes moléculaires à l’origine de la perturbation du métabolisme glucidique en réponse aux LPS permettra de mieux appréhender les conséquences physiologiques et pathologiques induites par ces molécules. / Lipopolysacharrides are molecules present on the surface of Gram (-) bacteria. In some situations, these molecules enter in the bloodstream. They induce an inflammatory reaction. Whatever the intensity of the response initiated by LPS, profound metabolic disturbances will take place. Carbohydrate metabolism is particularly affected. In humans, in cases of severe infection, such as sepsis, the strict control of LPS-induced hyperglycemia by insulin therapy is the subject of active research by the scientific and medical community. In addition, recent years have seen emerge the concept of metabolic endotoxemia, partly due to increased plasma concentrations of LPS as a result of high fat diets. These LPS molecules could be one of the many factors involved in the etiology of metabolic diseases. In this context, we investigated the glucose response during different experimental endotoxemia. Exclusively based on the study of various animal models, our experimental approach allowed us to demonstrate that the acute injection or continuous infusion of LPS, was accompanied by an increased glucose-stimulated insulin secretion associated with an increase of glucose disposal. We also demonstrated that this enhanced insulin secretion was due to an increase in circulating levels of glucagon-like peptide-1 (GLP-1) and that theGLP-1 receptor was involved in this response. Elucidating the molecular mechanisms underlying the disruption of glucose metabolism in response to LPS will enhance our understanding of the physiological and pathological consequences of these molecules.

Orientador: Lício Augusto Velloso / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-27T15:03:00Z (GMT). No. of bitstreams: 1 Silva_CarinaSolon_D.pdf: 1769268 bytes, checksum: b8a449a504bd2aa54bb737ba42860093 (MD5) Previous issue date: 2015 / Resumo: / Resumo: A interleucina-17 (IL17) está envolvida na resposta imune contra agentes patogénicos intestinais, e a sua expressão anómala no intestino pode ocorrer em condições tais como diabetes do tipo 1 (DM1), encefalomielite auto-imune e doença de Crohn. Fatores dietéticos podem alterar a microbiota intestinal desencadeando doenças metabólicas. Nossa hipótese é de que IL17 poderia ser diretamente modulada por nutrientes e pode desempenhar um papel na obesidade e diabetes tipo 2 (DM2). Aqui, nós demonstramos que as gorduras da dieta induzem a expressão IL17, predominantemente no íleo. In vivo, ilhotas pancreáticas isoladas estimuladas com IL17 apresentaram um aumento na secreção de insulina quando comparado a ilhotas não estimuladas, enquanto que a sua inibição sistémica resultou em intolerância à glicose. Animais knockout para o receptor de IL17 (IL17RA) eram intolerantes à glucose devido ao desenvolvimento embrionário anómalo das ilhotas pancreáticos, que eram menores e foram depletados de células produtoras de insulina. Nos seres humanos, os níveis circulantes de IL17 aumentaram após uma refeição. Este aumento foi significativamente maior nos indivíduos obesos normoglicêmicos do que em indivíduos obesos com diabetes. Semelhantes aos roedores, as ilhotas humanos também foram estimulados a secretarem insulina na presença de IL17. Assim nós identificamos a IL17 como um sensor intestinal de gorduras alimentares, que exerceram um efeito semelhante a hormônios incretínicos. Além disso, a presença IL17RA é importante para o desenvolvimento normal das ilhotas pancreáticas. / Abstract: / Abstract: Interleukin-17 (IL17) is involved in the immune response against intestinal pathogens, and its anomalous expression in the gut can occur in conditions such as type 1 diabetes (T1D) 1, autoimmune encephalomyelitis 2 and Crohn¿sdisease 3. Because dietary factors can change the gut microbiota, impacting metabolic diseases 4, we hypothesized that IL17 could be directly modulated by nutrients and might play a role in obesity and type 2 diabetes (T2D). Here, we show that dietary fats induced IL17 expression, predominantly in the ileum. Both in vivo and in isolated pancreatic islets, IL17 stimulated insulin secretion, while its systemic inhibition resulted in glucose intolerance. Mice KO for the main IL17 receptor (IL17RA) were glucose intolerant due to anomalous embryonic development of the pancreatic islets, which were smaller and were depleted of insulin-producing cells. In humans, blood IL17 increased following a meal. This increase was significantly higher in obese normoglycemic individuals than in obese subjects with diabetes. Similar to those of rodents, human islets were also stimulated to secrete insulin in the presence of IL17. Thus, we identified IL17 as a gut sensor of dietary fats, which exerted an incretin-like effect. In addition, the presence IL17RA was important for normal development of the pancreatic islets / Doutorado / Fisiopatologia Médica / Doutora em Ciências

The discovery that bile acids act as endogenous ligands of the membrane receptor TGR5 and the nuclear receptor FXR increased their significance as regulators of cholesterol, glucose and energy metabolism. Activation of TGR5, expressed on enteroendocrine L cells, by bile acids caused secretion of GLP-1, which stimulates insulin secretion from pancreatic β cells. Expression of TGR5 on pancreatic islet cells and the direct effect of bile acids on the endocrine functions of pancreas, however, are not fully understood. The aim of this study was to identify expression of TGR5 in pancreatic islet cells and determine the effect of bile acids on insulin secretion. Expression of TGR5 was identified by quantitative PCR and western blot in islets from human and mouse, and in α (αTC1-6) and β (MIN6) cells. Release of insulin, glucagon and GLP-1 were measured by ELISA. The signaling pathways coupled to TGR5 activation were identified by direct measurements such as stimulation of G proteins, adenylyl cyclase activity, PI hydrolysis and intracellular Ca2+ in response to bile acids; and confirmed by the use of selective inhibitors that block specific steps in the signaling pathway. Our studies identified expression of TGR5 receptors in β cells and demonstrated that activation of these receptors by both pharmacological ligands (oleanolic acid (OA) and INT-777) and physiological ligand (lithocholic acid, LCA) induced insulin secretion. TGR5 receptors are also expressed in α cells and, activation of TGR5 by OA, INT-777 and LCA at 5 mM glucose induced release of glucagon, which is processed from proglucagon by the selective expression of prohormone convertase 2 (PC2). However, under hyperglycemia, activation of TGR5 in α cells augmented the glucose-induced increase in GLP-1 secretion, which in turn, stimulated insulin secretion. Secretion of GLP-1 from α cells reflected TGR5-mediated increase in PC1 promoter activity and PC1 expression, which selectively converts proglucagon to GLP-1. The signaling pathway activated by TGR5 to mediate insulin and GLP-1 secretion involved Gs/cAMP/Epac/PLC-ε/Ca2+. These results provide insights into the mechanisms involved in the regulation of pancreatic α and β cell function by bile acids and may lead to new therapeutic avenues for the treatment of diabetes.

INTRODUÇÃO: O diabetes mellitus tipo 2 (DM2) é uma doença correlacionada com a obesidade mórbida. O paciente obeso apresenta efeito incretínico suprimido e consequente desbalanço da homeostase glicêmica. Diversos estudos evidenciam a melhora do DM2 após a confecção da Gastroplastia com derivação intestinal em Y de Roux (GDYR). Os mecanismos de controle da glicemia podem ser de longo e curto prazo. Os mecanismos de ação precoce estão ligados à restrição calorica, melhora da resistência insulínica, da função da célula beta pancreática e retorno do efeito incretínico pelo aumento do GLP1 e GIP, porém os dados são conflitantes. MÉTODOS: Onze pacientes obesos graves diabéticos foram submetidos à GDYR com confecção de gastrostomia no remanescente gástrico após perda de peso inicial de 10%. Os pacientes foram submetidos à coleta de entero-hormônios, perfil glicêmico e Teste de Tolerância Oral à glicose (TTOG) no pré-operatório em curva temporal que foi comparado ao pós-operatório por Via Oral e por Via da Gastrostomia em até 7 dias após o procedimento. RESULTADOS: A média da idade foi 46,09±7,08 anos. No pré-operatorio, o peso médio foi 120,97±17,02 quilogramas, altura 1,67±0,11 metros, IMC médio 44,06±6,59 kg/m2, glicemia de jejum média 194,55±62,45 mg/dl e hemoglobina glicada 8,74±1,64%. Em 77,7% dos pacientes, houve remissão precoce do DM2 no pós-operatório avaliado pelo TTOG. Também foi observada queda significante da glicemia, insulinemia e do HOMA-IR independente da via administrada. Ocorreu aumento significativo do GLP1 e redução do GIP pela Via Oral pós-operatória. A Grelina não apresentou alterações. CONCLUSÃO: Evidenciou-se redução da glicemia e da resistência periférica nos primeiros dias de pós-operatório da GDYR, independente da via de passagem do alimento. A alteração no efeito incretínico (aumento do GLP1 e redução do GIP) só foi observada na Via Oral pós-operatória / INTRODUCTION: Type 2 diabetes mellitus (DM2) is a disease correlated with morbidly obesity. The obese patient has a suppressed incretin effect and consequent inbalance of glycemic homeostasis. Several studies have shown an improvement in DM2 after Gastroplasty with Roux-en-Y gastric bypass (RYGB). The mechanisms of glycemic control may be long-term and shortterm. The mechanisms of early action are linked to caloric restriction, improvement of insulin resistance, pancreatic beta cell function and return of the incretin effect through the increase of GLP1 and GIP, but the data are conflicting. METHODS: Eleven diabetic obese patients underwent RYGB with gastrostomy in gastric remnant after initial 10% weight loss. Patients were submitted to assessment of enterohormones, glycemic profile and Oral Glucose Tolerance Test (OGTT) in the preoperative period in a time curve that was compared to the postoperative period by Oral Via and Gastrostomy Via up to 7 days after the procedure .RESULTS: The mean age of the group was 46.09 ± 7.08 years. In the preoperative the mean weight was 120.97 ± 17.02 kilograms, height of 1.67 ± 0.11 meters, mean BMI of 44.06 ± 6, 59 kg/m2, mean fasting blood glucose of 194.55 ± 62.45 mg/dl and glycated hemoglobin 8.74 ± 1.64%. In 77.7% of the patients there was remission of DM2 in postoperative evaluated by the OGTT. Significant decrease in glycemia, insulinemia and HOMA-IR was also observed, regardless of the route of administration. There was a significant increase in GLP1 and reduction of GIP by the postoperative oral route. Ghrelin did not change. CONCLUSION: A reduction in glycemia and peripheral insulinal resistance was observed in early postoperative days of RYGB, independent of the food route. The change in incretin effect (increase of GLP1 and reduction of GIP) was only observed in the postoperative oral route

INTRODUÇÃO: O diabetes mellitus tipo 2 (DM2) é uma doença correlacionada com a obesidade mórbida. O paciente obeso apresenta efeito incretínico suprimido e consequente desbalanço da homeostase glicêmica. Diversos estudos evidenciam a melhora do DM2 após a confecção da Gastroplastia com derivação intestinal em Y de Roux (GDYR). Os mecanismos de controle da glicemia podem ser de longo e curto prazo. Os mecanismos de ação precoce estão ligados à restrição calorica, melhora da resistência insulínica, da função da célula beta pancreática e retorno do efeito incretínico pelo aumento do GLP1 e GIP, porém os dados são conflitantes. MÉTODOS: Onze pacientes obesos graves diabéticos foram submetidos à GDYR com confecção de gastrostomia no remanescente gástrico após perda de peso inicial de 10%. Os pacientes foram submetidos à coleta de entero-hormônios, perfil glicêmico e Teste de Tolerância Oral à glicose (TTOG) no pré-operatório em curva temporal que foi comparado ao pós-operatório por Via Oral e por Via da Gastrostomia em até 7 dias após o procedimento. RESULTADOS: A média da idade foi 46,09±7,08 anos. No pré-operatorio, o peso médio foi 120,97±17,02 quilogramas, altura 1,67±0,11 metros, IMC médio 44,06±6,59 kg/m2, glicemia de jejum média 194,55±62,45 mg/dl e hemoglobina glicada 8,74±1,64%. Em 77,7% dos pacientes, houve remissão precoce do DM2 no pós-operatório avaliado pelo TTOG. Também foi observada queda significante da glicemia, insulinemia e do HOMA-IR independente da via administrada. Ocorreu aumento significativo do GLP1 e redução do GIP pela Via Oral pós-operatória. A Grelina não apresentou alterações. CONCLUSÃO: Evidenciou-se redução da glicemia e da resistência periférica nos primeiros dias de pós-operatório da GDYR, independente da via de passagem do alimento. A alteração no efeito incretínico (aumento do GLP1 e redução do GIP) só foi observada na Via Oral pós-operatória / INTRODUCTION: Type 2 diabetes mellitus (DM2) is a disease correlated with morbidly obesity. The obese patient has a suppressed incretin effect and consequent inbalance of glycemic homeostasis. Several studies have shown an improvement in DM2 after Gastroplasty with Roux-en-Y gastric bypass (RYGB). The mechanisms of glycemic control may be long-term and shortterm. The mechanisms of early action are linked to caloric restriction, improvement of insulin resistance, pancreatic beta cell function and return of the incretin effect through the increase of GLP1 and GIP, but the data are conflicting. METHODS: Eleven diabetic obese patients underwent RYGB with gastrostomy in gastric remnant after initial 10% weight loss. Patients were submitted to assessment of enterohormones, glycemic profile and Oral Glucose Tolerance Test (OGTT) in the preoperative period in a time curve that was compared to the postoperative period by Oral Via and Gastrostomy Via up to 7 days after the procedure .RESULTS: The mean age of the group was 46.09 ± 7.08 years. In the preoperative the mean weight was 120.97 ± 17.02 kilograms, height of 1.67 ± 0.11 meters, mean BMI of 44.06 ± 6, 59 kg/m2, mean fasting blood glucose of 194.55 ± 62.45 mg/dl and glycated hemoglobin 8.74 ± 1.64%. In 77.7% of the patients there was remission of DM2 in postoperative evaluated by the OGTT. Significant decrease in glycemia, insulinemia and HOMA-IR was also observed, regardless of the route of administration. There was a significant increase in GLP1 and reduction of GIP by the postoperative oral route. Ghrelin did not change. CONCLUSION: A reduction in glycemia and peripheral insulinal resistance was observed in early postoperative days of RYGB, independent of the food route. The change in incretin effect (increase of GLP1 and reduction of GIP) was only observed in the postoperative oral route

Patients with type II diabetes present alterations in glucose homeostasis due to insufficient amount of insulin (β-cell dysfunction) and inability to properly use the insulin that is secreted (insulin resistance). Combined genetical and environmental factors are believed to be responsible for these dysfunctions and the resulting impairment in glucose homeostasis. The pancreatic gland is composed of exocrine and endocrine tissues. The endocrine part of the organ couples glucose sensing to insulin release. Within this endocrine gland, also known as islets of Langerhans, the insulin secreting β-cell is the main player and therefore highly important for proper glucose metabolism. In this thesis, mice were developed in order to assess the role of BMP signaling molecule and Arsenite induced ATPase-1 (Asna1) for pancreas development and β-cell function. The mature β-cell responds to elevated glucose levels by secreting insulin in a tightly controlled manner. This physiological response of the β-cell to elevated blood glucose levels is critical for maintenance of normoglycaemia and impaired Glucose stimulated insulin secretion (GSIS) is a prominent feature of overt type 2 diabetes. Thus, the identification of signals and pathways that ensure and stimulate GSIS in β-cells is of great clinical interest. Here we show (Paper I) that BMPRIA and its high affinity ligand BMP4 are expressed in fetal and adult islets. We also provide evidence that BMPRIA signaling in adult β-cell is required for GSIS, and that both transgenic expression of Bmp4 in β-cells or systemic administration of BMP4 protein to mice enhances GSIS. Thus, BMP4-BMPRIA signaling in β-cells positively regulates the genetic machinery that ensures GSIS. Arsenite induced ATPase (Asna1), the homologue of the bacterial ArsA ATPase, is expressed in insulin producing cells of both mammals and the nematode Caenorhabditis elegans (C.elegans). Asna1 has been proposed to act as an evolutionary conserved regulator of insulin/insulin like factor signaling. In C.elegans, asna-1 has been shown to regulate growth in a non-cell autonomous and IGF-receptor dependent manner. Here we show that transgenic expression of ASNA1 in β-cells of mice leads to enhanced Aktactivity and β-cell hyperplasia (manuscript). ASNA1 transgenic mice develop, however, diabetes due to impaired insulin secretion. The expression of genes involved in secretion stimulus coupling and insulin exocytosis is perturbed in islets of these mice. These data suggest that activation of ASNA1, here mimicked by enhanced expression, positively influences β-cell mass but negatively affects insulin secretion.