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)

We examined the responses of basilar arteries taken from Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a type 2 diabetes model. Both the nitric oxide (NO)-mediated relaxation and the cyclic 3',5'-guanosine monophosphate (cGMP) production elicited by acetylcholine (ACh) were much weaker in OLETF rats than in age-matched control Long Evans Tokushima Otsuka (LETO) rats. The contraction induced by an NO synthase (NOS) inhibitor [N(G)-nitro-L-arginine (L-NNA)] was weaker in the OLETF group. In that group, application of apocynin, an NAD(P)H oxidase inhibitor, normalized (i) ACh-induced relaxation, (ii) L-NNA-induced contraction, and (iii) ACh-induced cGMP production to the LETO levels. Superoxide anion production was greater in basilar arteries from OLETF rats than in those from LETO rats. The protein expression of gp91(phox), an NAD(P)H oxidase subunit, was upregulated in the OLETF arteries (versus LETO ones). These results suggest that the existence of endothelial dysfunction in basilar arteries in type 2 diabetes is related to increased oxidative stress mediated via NAD(P)H oxidase. Possibly, an impairment of NO-dependent relaxation responses and a basal impairment of NO signaling may be responsible for the increased risk of adverse cerebrovascular events in type 2 diabetes.
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PMID:Vascular NAD(P)H oxidase mediates endothelial dysfunction in basilar arteries from Otsuka Long-Evans Tokushima Fatty (OLETF) rats. 1683 40

Insulin-regulated membrane aminopeptidase (IRAP) translocates to the plasma membrane with glucose transporter-4 (GLUT4) on insulin stimulation. However, this may be impaired in patients at risk of diabetes. Recently a novel technique has been developed to assess cell surface IRAP activity dynamically using a fluorogenic membrane impermeable substrate. In this study we measured the cell surface IRAP activity and 3-O-[methyl-14C]-D-Glucose uptake in adipocytes isolated from Otsuka Long Evans Tokushima Fatty rats (OLETF), developed as a model of type 2 diabetes mellitus, to evaluate whether the translocation of GLUT4/IRAP vesicles is affected. On the addition of insulin, the cell surface IRAP activity promptly increased to reach equilibrium in a hormone dose-dependent manner. OLETF rats showed significantly lower equilibrium activity than control rats (P<0.01). Time to reach the equilibrium was also significantly longer in the OLETF case, and adipocytes isolated from OLETF rats demonstrated both a delay and a reduction in 3-O-[methyl-14C]-D-Glucose uptake. This impairment in all parameters was alleviated by treatment with pioglitazone. Continuous measurement of cell surface IRAP activity allowed accurate evaluations of GLUT4/IRAP vesicle translocation and of the establishment of defects in OLETF rats.
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PMID:Impaired insulin-regulated membrane aminopeptidase translocation to the plasma membrane in adipocytes of Otsuka Long Evans Tokushima Fatty rats. 1696 82

Several clinical cohort and case-control studies have suggested a link between diabetes and colon cancer. Otsuka Long-Evans Tokushima Fat (OLETF) rats spontaneously develop type 2 diabetes mellitus and Long-Evans Tokushima Otsuka (LETO) rats are non-diabetic. The relationship between type 2 diabetes mellitus and colon cancer was examined in these rats. The carcinogen 1,2-dimethylhydrazine was administered subcutaneously once weekly for 10 weeks, and the animals were killed and necropsied in week 29. All OLETF rats and 80% of the LETO rats developed cancer. The number of colon cancers per rat was significantly greater in the diabetic than in the non-diabetic rats. Although the tumours tended to be larger in diabetic rats, the difference was not statistically significant. No significant differences were observed in the depth of invasion or histological type of cancer in the two groups. Type 2 diabetes mellitus may enhance the generation and growth of colon cancer.
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PMID:Greater development of 1,2-dimethylhydrazine-induced colon cancer in a rat model of type 2 diabetes mellitus. 1698 94

The Otsuka Long-Evans Tokushima fatty rat is an animal model of Type 2 diabetes mellitus (DM), which is characterized by diastolic dysfunction associated with decreased sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a). The aim of this study was to examine whether gene transfer of SERCA2a can influence coronary blood flow and cardiomyocyte diameter in this model. DM rats were injected with adenovirus carrying SERCA2a (DM+SERCA) or beta-galactosidase gene (DM+betaGal). Coronary blood flow was measured in cross-circulated excised hearts 3 days after infection. Although in all groups coronary blood flow remained unchanged even if left ventricular (LV) volume or intracoronary Ca(2+) infusion was increased, the DM+SERCA group showed a sustained increase in coronary blood flow compared with the other groups. This result suggests that the sustained high coronary blood flow is a specific response in SERCA2a-overexpressed hearts. Although the LV weight-to-body weight ratio (LV/BW) and cardiomyocyte diameter were higher in the DM and DM+betaGal groups than in the non-DM group, in the DM+SERCA group, these measurements were restored to non-DM size. The percentages of collagen area in the three DM groups was significantly higher than results shown in non-DM rats, and there were no significant differences in collagen area percentage among the three DM groups. These results suggest that a lowered LV/BW by SERCA2a overexpression is due mainly to reduced size of cardiomyocytes without any changes in collagen area percentage. In conclusion, in DM failing hearts, SERCA2a gene transfer can increase coronary blood flow and reduce cardiomyocyte size without reduction in collagen production.
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PMID:Transcoronary gene transfer of SERCA2a increases coronary blood flow and decreases cardiomyocyte size in a type 2 diabetic rat model. 1701 46

Increased apoptosis of pancreatic beta-cells plays an important role in the occurrence and development of type 2 diabetes. We examined the effect of diazoxide on pancreatic beta-cell apoptosis and its potential mechanism in Otsuka Long Evans Tokushima Fatty (OLETF) rats, an established animal model of human type 2 diabetes, at the prediabetic and diabetic stages. We found a significant increase with age in the frequency of apoptosis, the sequential enlargement of islets, and the proliferation of the connective tissue surrounding islets, accompanied with defective insulin secretory capacity and increased blood glucose in untreated OLETF rats. In contrast, diazoxide treatment (25 mg.kg(-1).d(-1), administered ip) inhibited beta-cell apoptosis, ameliorated changes of islet morphology and insulin secretory function, and increased insulin stores significantly in islet beta-cells whether diazoxide was used at the prediabetic or diabetic stage. Linear regression showed the close correlation between the frequency of apoptosis and hyperglycemia (r = 0.913; P < 0.0001). Further study demonstrated that diazoxide up-regulated Bcl-2 expression and p38beta MAPK, which expressed at very low levels due to the high glucose, but not c-jun N-terminal kinase and ERK. Hence, diazoxide may play a critical role in protection from apoptosis. In this study, we demonstrate that diazoxide prevents the onset and development of diabetes in OLETF rats by inhibiting beta-cell apoptosis via increasing p38beta MAPK, elevating Bcl-2/Bax ratio, and ameliorating insulin secretory capacity and action.
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PMID:Diazoxide prevents diabetes through inhibiting pancreatic beta-cells from apoptosis via Bcl-2/Bax rate and p38-beta mitogen-activated protein kinase. 1705 28

In a prior study, we reported on a significant decrease in calpain10 gene expression in white blood cells (WBC) as well as the major insulin-target tissues including liver and adipose tissue, before the onset of diabetes in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. In this study, we extended our hypothesis that some type 2 diabetes mellitus (NIDDM) susceptible genes are up/down-regulated before the onset in WBC of OLETF rats, reflecting their up/down-regulation in major insulin-target tissues, such as the liver. We tested this hypothesis using rat cDNA microarrays. The findings show that 1080 genes are up/down-regulated by more than 2-fold compared to the controls, Long-Evans Tokushima Otsuka rats, before the onset in WBC and liver under fasted or insulin administered condition. Fifty-seven of the 1080 genes were up/down-regulated in both WBC and the liver. More than half have been reported to NIDDM susceptible genes and the remainder have not been reported to be related to NIDDM. These results indicate that there some NIDDM related genes are up/down-regulated in WBC before the onset of diabetes.
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PMID:Genome wide expression analysis of white blood cells and liver of pre-diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats using a cDNA microarray. 1714 81

Both mitochondrial dysfunction and alterations in mitochondrial DNA (mtDNA) are implicated in type 2 diabetes mellitus and insulin resistance. Evidence also suggests that metabolism of S-adenosyl-L-methionine (SAM), the universal methyl donor for biological methylation, is associated with mitochondrial dysfunction and insulin resistance. We investigated the effect of SAM on mtDNA density and insulin sensitivity using the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an animal model of type 2 diabetes mellitus and insulin resistance. To determine the short-term effect on mtDNA density, SAM (15 mg.kg-1.d-1) was administered intraperitoneally for 7 d to 6 male, 57-wk-old OLETF rats and 6 Long-Evans Tokushima Otsuka (LETO) rats of the same age as a nondiabetic control. To determine the long-term effect, the same dose of SAM was administered daily to 5 male, 6-wk-old OLETF rats until the age of 25 wk; 7 control OLETF rats received vehicle and 7 LETO rats were untreated. Skeletal muscle mtDNA density was measured by either competitive or multiplex PCR and insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp. SAM treatment for 1 wk increased skeletal muscle mtDNA density of both OLETF and LETO rats. The long-term SAM treatment significantly reduced body weight gain as well as increased skeletal muscle mtDNA density and whole body insulin sensitivity in OLETF rats compared with their vehicle-treated controls. Furthermore, in all 3 groups, skeletal muscle mtDNA density correlated with insulin sensitivity (r=0.752, P<0.001). In conclusion, SAM treatment increased mtDNA density in the skeletal muscle, improved whole body insulin sensitivity, and prevented body weight gain in OLETF rats.
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PMID:S-adenosyl-L-methionine increases skeletal muscle mitochondrial DNA density and whole body insulin sensitivity in OLETF rats. 1723 8

In a previous study, we hypothesized that some type 2 diabetes mellitus susceptible genes may be up/down-regulated in white blood cells (WBC) of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, reflecting their up/down-regulation in major insulin-target tissues such as the liver before the onset of diabetes. We identified 57 potential candidate genes for predicting diabetes. In this study, we examined this hypothesis further by extending the experimental conditions from before the onset (6 weeks) to after the onset (24 weeks) of diabetes that type 2 diabetes mellitus susceptible genes are co-regulated in WBC, reflecting their expression in the liver. Using rat oligo DNA microarrays, we found that 48 genes are up/down-regulated in OLETF rats compared to control Long-Evans Tokushima Otsuka (LETO) rats in WBC and liver under fasting or insulin administration conditions. Twenty nine and 33 genes were up/down-regulated in both WBC and livers, respectively, under fasting and insulin administration conditions, respectively. Eight out of 29 genes in fasting condition and 12 out of 33 genes in insulin administration conditions have been reported to be type 2 diabetes mellitus susceptible genes and the remainder have not been reported to be related to type 2 diabetes mellitus. These results support our hypothesis that the expression levels of type 2 diabetes mellitus related genes in WBC are reflective of those in the liver after the onset of diabetes.
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PMID:DNA microarray analysis of type 2 diabetes-related genes co-regulated between white blood cells and livers of diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. 1740 17

Treatment with rosiglitazone, a potent peroxisome proliferator-activated receptor (PPAR) gamma agonist, results in lipid storage coupled with reduced release of free fatty acids into the circulation. Many studies have reported that PPAR-gamma agonists increase subcutaneous adiposity but have no effect on visceral fat mass. Perilipin, a family of phosphoproteins that coat intracellular lipid droplets in adipocytes, is essential for enlargement of lipid droplets. Recently, a functional PPAR-responsive element was identified within the murine perilipin gene. We hypothesized that the depot-specific regulation of perilipin by rosiglitazone may be associated with the fat-redistribution and insulin-sensitizing effects of rosiglitazone. After 6 weeks of rosiglitazone treatment in Otusuka Long-Evans Tokushima Fatty rats, an animal model of type 2 diabetes mellitus, we measured changes in adiposity, triglyceride content in liver and muscle, morphology of the pancreas, and perilipin messenger RNA and protein expression in adipose tissue. Rosiglitazone increased subcutaneous adiposity, decreased triglyceride content of liver and muscle, decreased plasma free fatty acids (2107 +/- 507 micromol/L in the placebo group vs 824 +/- 148 micromol/L in the rosiglitazone group; P < .05), and improved insulin resistance. The islets of placebo-treated rats showed hypertrophy and destruction, whereas the islets of rosiglitazone-treated rats showed hypertrophy, but the islet architecture remained intact. Perilipin messenger RNA and protein expression increased in subcutaneous fat, but did not change in visceral fat, after rosiglitazone treatment. In 3T3-L1 cells, rosiglitazone pretreatment decreased lipolysis and increased perilipin protein. In conclusion, increased perilipin expression in subcutaneous fat after rosiglitazone treatment is likely to be a mediator of reduced lipolysis, resulting in lipid storage in subcutaneous fat, fat redistribution, and insulin sensitization.
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PMID:Depot-specific regulation of perilipin by rosiglitazone in a diabetic animal model. 1744 44

Acetate has been found to have an inhibitory effect on the activity of carbohydrate-responsive element-binding protein (ChREBP) in cultured hepatocytes, this being a transcription factor that regulates several genes required for the conversion of glucose to fatty acids in the liver. The aim of this study was to investigate whether an oral administration of acetate would contribute to reducing lypogenic genes and protecting against obesity. We orally injected 5.2 mg/kg BW of acetate to obesity-linked type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. The treatment with acetate showed a marked reduction in lipid accumulation in the adipose tissue, protection against accumulation of fat in the liver, and improved glucose tolerance. An analysis by Northern blotting revealed that the transcripts of several lipogenic genes in the liver of OLETF rats were decreased by the acetate treatment. On the basis of those results, it was indicated that acetate was a potential compound to improve obesity and obesity-linked type 2 diabetes.
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PMID:Improvement of obesity and glucose tolerance by acetate in Type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. 1748 60


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