Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The escalating rates of obesity and type 2 diabetes have reached pandemic proportions. It has been proposed that the risk of developing metabolic disorders in adult life is influenced by environmental factors, which operate during the early periods of development. We have previously shown that an interaction between the prenatal and the postnatal dietary environment amplifies the propensity towards diet-induced obesity, although the mechanisms are unclear. In the present study, we investigated the interaction between prenatal undernutrition and postnatal high-fat nutrition on key genes of the hypothalamic appetite regulatory network. Pregnant Wistar rats were fed a standard chow diet either ad libitum (AD) or at 30% of AD intake throughout gestation (UN). From weaning, female AD and UN offspring were fed either a standard chow (ADC n = 8, UNC n = 8) or a high-fat diet (45% kcal as fat; ADHF n = 8, UNHF n = 8) ad libitum for the remainder of the study. At 24 weeks of age, body composition was assessed by dual energy X-ray absorptiometry analysis and total RNA was extracted from whole rat hypothalami. Real-time PCR was performed to characterise pro-opiomelanocortin (POMC), neuropeptide Y (NPY), agouti-related protein (AgRP) and OBRb gene expression at the mRNA level. Our results demonstrate that the amplification of postnatal obesity develops as a consequence of an interaction between prenatal under-nutrition and postnatal high-fat nutrition. This phenotype also shows significant alterations in POMC, NPY, AgRP and OBRb gene expression together with elevations in circulating levels of both plasma leptin and insulin. These findings are consistent with the predictive adaptive response hypothesis that neuroendocrine development during fetal life may be based on predictions about postnatal environmental conditions. Increased susceptibility to diet-induced obesity develops if a mismatch between the anticipated and the actual conditions are encountered.
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PMID:Prenatal influences on susceptibility to diet-induced obesity are mediated by altered neuroendocrine gene expression. 1740 Aug

Insulin action in the central nervous system regulates energy homeostasis and glucose metabolism. To define the insulin-responsive neurons that mediate these effects, we generated mice with selective inactivation of the insulin receptor (IR) in either pro-opiomelanocortin (POMC)- or agouti-related peptide (AgRP)-expressing neurons of the arcuate nucleus of the hypothalamus. While neither POMC- nor AgRP-restricted IR knockout mice exhibited altered energy homeostasis, insulin failed to normally suppress hepatic glucose production during euglycemic-hyperinsulinemic clamps in AgRP-IR knockout (IR(DeltaAgRP)) mice. These mice also exhibited reduced insulin-stimulated hepatic interleukin-6 expression and increased hepatic expression of glucose-6-phosphatase. These results directly demonstrate that insulin action in POMC and AgRP cells is not required for steady-state regulation of food intake and body weight. However, insulin action specifically in AgRP-expressing neurons does play a critical role in controlling hepatic glucose production and may provide a target for the treatment of insulin resistance in type 2 diabetes.
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PMID:Insulin action in AgRP-expressing neurons is required for suppression of hepatic glucose production. 1755 Jul 79

A subset of neurons in the brain, known as 'glucose-excited' neurons, depolarize and increase their firing rate in response to increases in extracellular glucose. Similar to insulin secretion by pancreatic beta-cells, glucose excitation of neurons is driven by ATP-mediated closure of ATP-sensitive potassium (K(ATP)) channels. Although beta-cell-like glucose sensing in neurons is well established, its physiological relevance and contribution to disease states such as type 2 diabetes remain unknown. To address these issues, we disrupted glucose sensing in glucose-excited pro-opiomelanocortin (POMC) neurons via transgenic expression of a mutant Kir6.2 subunit (encoded by the Kcnj11 gene) that prevents ATP-mediated closure of K(ATP) channels. Here we show that this genetic manipulation impaired the whole-body response to a systemic glucose load, demonstrating a role for glucose sensing by POMC neurons in the overall physiological control of blood glucose. We also found that glucose sensing by POMC neurons became defective in obese mice on a high-fat diet, suggesting that loss of glucose sensing by neurons has a role in the development of type 2 diabetes. The mechanism for obesity-induced loss of glucose sensing in POMC neurons involves uncoupling protein 2 (UCP2), a mitochondrial protein that impairs glucose-stimulated ATP production. UCP2 negatively regulates glucose sensing in POMC neurons. We found that genetic deletion of Ucp2 prevents obesity-induced loss of glucose sensing, and that acute pharmacological inhibition of UCP2 reverses loss of glucose sensing. We conclude that obesity-induced, UCP2-mediated loss of glucose sensing in glucose-excited neurons might have a pathogenic role in the development of type 2 diabetes.
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PMID:Glucose sensing by POMC neurons regulates glucose homeostasis and is impaired in obesity. 1772 16

Diabetes mellitus type 2 (DM type 2) is associated with depressive symptomatology and intermittent hyperfunction of the hypothalamic-pituitary-adrenal (HPA) axis. DM type 2 is also accompanied by increased tissue levels of angiotensin II (Ang II), which stimulates the HPA axis through the Ang II type 1 receptors (AT1). We investigated the effect of candesartan, an angiotensin receptor blocker (ARB) that crosses the blood brain barrier, on the activity of the HPA axis and on the affect of 17 patients with DM type 2, aged 40-65 years, who were treated with 4 mg/day candesartan per os for at least 3 months. Before and after candesartan administration, a corticotropin-releasing hormone (CRH) stimulation test and psychological tests were performed. In response to hCRH, time-integrated secretion of ACTH was not altered by candesartan administration, however, the cortisol response was decreased significantly compared to baseline (mean +/- SEM, 2327 +/- 148.3 vs. 1943 +/- 131.9 microg/dl, P = 0.005) suggesting reduced sensitivity of the adrenals to ACTH. In parallel, there was a significant improvement in interpersonal sensitivity (0.91 +/- 0.16 vs. 0.70 +/- 0.15, P = 0.027) and depression scores (0.96 +/- 0.15 vs. 0.71 +/- 0.10, P = 0.026). We suggest that candesartan resets the HPA axis of patients with DM type 2 and improves their affect.
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PMID:Chronic administration of an angiotensin II receptor antagonist resets the hypothalamic-pituitary-adrenal (HPA) axis and improves the affect of patients with diabetes mellitus type 2: preliminary results. 1785 61

In diabetes, dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) axis causes effects such as elevation of corticotropin (ACTH) and glucocorticoids. Cholecystokinin and its receptors are involved in the HPA axis and influence the regulation of the HPA axis. We examined adrenocortical function in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes mellitus, that lack the cholecystokinin A receptor. We measured adrenal weight, plasma ACTH, serum and urinary corticosterone, and serum leptin in OLETF rats at 5 to 36 weeks of age. Messenger RNA (mRNA) expression of 11beta-hydroxysteroid dehydrogenase and 5alpha-reductase type 1 in adrenal glands of the rats were examined. Long-Evans Tokushima Otsuka (LETO) rats were used as controls. In OLETF rats at 32 to 36 weeks of age, plasma ACTH was significantly higher (P < .001); serum corticosterone and 24-hour urinary corticosterone were significantly lower (P < .005); and adrenal weight was significantly lower (P < .005) than those in LETO rats. At the same ages, serum leptin in OLETF rats was significantly higher (P < .001) than that in LETO rats. In the younger OLETF rats, these changes were not observed. Overall, there was an inverse correlation between serum corticosterone and serum leptin (r = -0.374, P < .0005), whereas there was a positive correlation between plasma ACTH and serum leptin (r = 0.654, P < .0001). At 5 and 36 weeks of age, mRNA expression of 5alpha-reductase type 1 in the adrenal gland of OLETF rats was significantly higher (P < .05) than that of LETO rats, whereas there was no significant difference in mRNA expressions of 11beta-hydroxysteroid dehydrogenase types 1 and 2. We showed that adrenocortical insufficiency and adrenal atrophy were acquired in OLETF rats, and the possibility of elevated serum leptin relates to this phenomenon.
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PMID:Adrenocortical insufficiency in Otsuka Long-Evans Tokushima Fatty rats, a type 2 diabetes mellitus model. 1788 40

A growing body of evidence suggests that maternal undernutrition sensitizes the offspring to the development of energy balance metabolic disorders such as type 2 diabetes, dyslipidemia, and obesity. The present study aimed at examining the impact of maternal undernutrition on leptin plasma levels in newborn male rats and on the arcuate nucleus proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons that are major leptin targets. Using a model of perinatal maternal 50% food-restricted diet (FR50) in the rat, we evaluated leptin plasma levels and hypothalamic POMC and NPY gene expression from postnatal day (PND) 4 to PND30 in both control and FR50 offspring. In control rats, a postnatal peak of plasma leptin was observed between PND4 and PND14 that reached a maximal value at PND10 (5.17 +/- 0.53 ng/ml), whereas it was dramatically reduced in FR50 pups with the higher concentration at PND7 (0.93 +/- 0.23 ng/ml). In FR50 animals, using semiquantitative RT-PCR and in situ hybridization, we showed that the hypothalamic POMC mRNA level was decreased from PND14 until PND30, whereas NPY gene expression was not significantly modified. In PND21 FR50 animals, we observed strikingly reduced immunoreactive beta-endorphin nerve fibers projecting to the hypothalamic paraventricular nucleus without affecting NPY projections. Our data showed that maternal undernutrition drastically reduces the postnatal surge of plasma leptin, disturbing particularly the hypothalamic wiring as well as the gene expression of the anorexigenic POMC neurons in male rat pups. These alterations might contribute to the adult metabolic disorders resulting from perinatal growth retardation.
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PMID:Maternal perinatal undernutrition drastically reduces postnatal leptin surge and affects the development of arcuate nucleus proopiomelanocortin neurons in neonatal male rat pups. 1800 26

The various hormones, proteins and other compounds related to developing obesity, insulin resistance and type 2 diabetes are analyzed in the paper. 1) Leptin, ciliary neurutrophic factor, adiponectin, glucagon-like peptide 1, peptide YY, neuromedin S, as well as the protein receptors of these hormones decrease the food consumption, increase the energy turnover, and prevent obesity, insulin resistance, and type 2 diabetes development. The mediators of these hormone and receptor actions are melanocyte stimulating hormone (MSH), corticotropin-releasing hormone (CRH), and the others. 2) Ghrelin, endogenose cannabinoides, galanin-like peptide and the mediators of their actions: neuropeptide Y (NPY) and Agouti gene related protein (AGRP) increase the appetite and food consumption. Peroxisome proliferation-activated receptor (PPAR) performs the similar action on food intake. The activation of the first group compound functioning decreases the obesity, increases the energy turnover, facilitates the insulin action and prevents the insulin resistance and type 2 diabetes. Increasing the activities of the second group, as well as, decreasing the actions of the first one of substances induce the opposite effects and facilitate obesity, insulin resistance, and type 2 diabetes developments. The interconnections of the molecular mechanisms of so many hormone actions make the very complicated tusk to study the various endocrine disorders including diabetes mellitus as well.
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PMID:[The interconnections of molecular mechanisms of hormone actions and their role in pathogenesis of obesity, insulin resistance, and diabetes mellitus]. 1842 6

The objectives of this study were to identify potential alterations in gene expression of melanocortin-4 receptor (MC4-R), proopiomelanocortin (POMC), and Agouti-related protein (AgRP) in mouse hypothalamus under a chronic peripheral infusion of leptin or at early (8 weeks) and advanced (16 weeks) phases of diet-induced obesity. Control or diet-induced obesity mice (8 or 16 weeks of high-fat diet) were either treated or not treated with leptin. Metabolic features were analyzed and expression of the genes of interest was measured by quantitative reverse transcriptase-PCR (RT-qPCR) and western blot. We reported that in control mice, but not in obese mice, leptin infusion induced an increase in POMC mRNA level as well as in MC4-R mRNA level suggesting that leptin could act directly and/or through alpha-melanocyte-stimulating hormone (alpha-MSH). This hypothesis was reinforced after in vitro studies, using the mouse hypothalamic GT1-7 cell line, since both leptin and Norleucine(4), D-Phenylalanine(7)-alpha-MSH (NDP-alpha-MSH) treatments increased MC4-R expression. After 8 weeks of high-fat diet, nondiabetic obese mice became resistant to the central action of leptin and their hypothalamic content of POMC and AgRP mRNA were decreased without modification of MC4-R mRNA level. After 16 weeks of high-fat diet, mice exhibited more severe metabolic disorders with type 2 diabetes. Moreover, hypothalamic expression of MC4-R was highly increased. In conclusion, several alterations of the melanocortin system were found in obese mice that are probably consecutive to their central resistance to leptin. Moreover, when the metabolic status is highly degraded (with all characteristics of a type 2 diabetes), other regulatory mechanisms (independent of leptin) can also take place.
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PMID:Leptin infusion and obesity in mouse cause alterations in the hypothalamic melanocortin system. 1855 Nov 22

A 69-year-old man with type 2 diabetes mellitus was admitted to our hospital because of appetite loss, nausea and vomiting. Gastroscopy revealed gastric cancer. Levels of plasma cortisol were decreased. Neither adrenocorticotropic hormone (ACTH) nor cortisol levels were adequately increased in response to a mixed intravenous administration of corticotropin-releasing hormone, growth hormone-releasing hormone, thyrotropin-releasing hormone and lutenizing hormone-releasing hormone, although other pituitary hormones were increased adequately. He was diagnosed as having isolated ACTH deficiency (IAD). Anti-pituitary antibody and anti-parietal cell antibody were positive. At least in part, these antibodies may play pathogenic roles of development of IAD and gastric cancer.
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PMID:Type 2 diabetes mellitus accompanied by isolated adrenocorticotropic hormone deficiency and gastric cancer. 1952 93

The melanocortin-4 receptor (MC4R) is a G-protein-coupled receptor (GPCR) that is expressed in the central nervous system and has a role in regulating feeding behavior, obesity, energy homeostasis, male erectile response, and blood pressure. Since the report of the MC4R knockout mouse in 1997, the field has been searching for links between this genetic biomarker and human obesity and type 2 diabetes. More then 80 single nucleotide polymorphisms (SNPs) have been identified from human patients, both obese and nonobese controls. Many significant studies have been performed examining the pharmacological characteristics of these hMC4R SNPs in attempts to identify a molecular defects/insights that might link a genetic factor to the obese phenotype observed in patients possessing these mutations. Our laboratory has previously reported the pharmacological characterization of 40 of these polymorphic hMC4 receptors with multiple endogenous and synthetic ligands. The goal of the current study is to perform a similar comprehensive side-by-side characterization of 30 additional human hMC4R with single nucleotide polymorphisms using multiple endogenous agonists [alpha-, beta-, and gamma(2)-melanocyte stimulating hormones (MSH) and adrenocorticotropin (ACTH)], the antagonist agouti-related protein hAGRP(87-132), and synthetic agonists [NDP-MSH, MTII, and the tetrapeptide Ac-His-dPhe-Arg-Trp-NH(2) (JRH887-9)]. These in vitro data, in some cases, provide a putative molecular link between dysfunctional hMC4R's and human obesity. These 30 hMC4R SNPs include R7H, R18H, R18L, S36Y, P48S, V50M, F51L, E61K, I69T, D90N, S94R, G98R, I121T, A154D, Y157S, W174C, G181D, F202L, A219 V, I226T, G231S, G238D, N240S, C271R, S295P, P299L, E308K, I317V, L325F, and 750DelGA. All but the N240S hMC4R were identified in obese patients. Additionally, we have characterized a double I102T/V103I hMC4R. In addition to the pharmacological characterization, the hMC4R variants were evaluated for cell surface expression by flow cytometry. The F51L, I69T, and A219V hMC4Rs possessed full agonist activity and significantly decreased endogenous agonist ligand potency. At the E61K, D90N, Y157S, and C271R hMC4Rs, all agonist ligands examined were only partially efficacious in generating a maximal signaling response (partial agonists) and possessed significantly decreased endogenous agonist ligand potency. Only the A219V, G238D, and S295P hMC4Rs possessed significantly decreased AGRP(87-132) antagonist potency. These data provide new information for use in GPCR computational development as well as insights into MC4R structure ad function.
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PMID:Pharmacological characterization of 30 human melanocortin-4 receptor polymorphisms with the endogenous proopiomelanocortin-derived agonists, synthetic agonists, and the endogenous agouti-related protein antagonist. 2046 74


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