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)

Intracellular glucocorticoid (GC) receptor (GR) function determines tissue sensitivity to GCs and strongly affects the development of type 2 diabetes and obesity. 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) mediates intracellular steroid exposure to mouse liver GR by prereceptor reactivation of GCs and is crucially dependent on hexose-6-phosphate dehydrogenase (H6PDH)-generating NADPH system. Pharmacological inhibition of 11beta-HSD1 improves insulin intolerance and obesity. Here, we evaluated the potential beneficial effects of 11beta-HSD1 inhibitor carbenoxolone (CBX) in diet-induced obese (DIO) and insulin-resistant mice by examining the possible influence of CBX on the expression of GR, 11beta-HSD1, and H6PDH in vivo and in vitro in hepatocytes. Treatment of DIO mice with CBX markedly reduced hepatic GR mRNA levels and reduced weight gain, hyperglycemia, and insulin resistance. The reduction of hepatic GR gene expression was accompanied by CBX-induced inhibition of both 11beta-HSD1 and H6PDH activity and mRNA in the liver. Moreover, CBX treatment also suppressed the expression of both phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase enzyme (G6Pase) mRNA and improved hepatic [1, 2-(3)H] deoxy-d-glucose uptake in DIO mice. In addition, the treatment of primary cultures of hepatocytes with increasing concentrations of CBX led to a dose-dependent downregulation of GR mRNA levels, which correlated with the suppression of both 11beta-HSD1 and H6PDH activity and their gene expression. Addition of CBX to primary hepatocytes also resulted in suppression of both PEPCK and G6Pase mRNA levels. These findings suggest that CBX exerts some of its beneficial effects, at least in part, by inhibiting hepatic GR and H6PDH expression.
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PMID:Reduction of hepatic glucocorticoid receptor and hexose-6-phosphate dehydrogenase expression ameliorates diet-induced obesity and insulin resistance in mice. 1852 70

The enzyme glucose-6-phosphatase is critical for maintaining fasting blood sugar levels by increasing hepatic glucose production. Its absence in patients with von Gierke's disease leads to severe hypoglycemia and abnormal accumulation of glycogen (glycogenosis) in the liver. New players that control the expression of glucose-6-phosphatase have been identified that may provide insight into this metabolic disorder, as well as type 2 diabetes.
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PMID:Von Gierke's disease adopts an orphan (and its partner). 1903 40

The regulation of expression of gluconeogenic genes including glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) in the liver plays an important role in glucose homeostasis, because aberrant expression of these genes contributes to the development of type 2 diabetes. Previous reports demonstrate that signal transducer and activator of transcription 3 (STAT3) plays a key role in regulating gluconeogenic gene expression, but the mechanism remains unclear. Herein we demonstrate that phosphorylated STAT3 is required for repression of G6Pase expression by IL-6 in both HepG2 cells and mouse liver. Interestingly, PEPCK expression is regulated by STAT3 independent of IL-6 activation. Using in vivo chromatin immunoprecipitation, we demonstrate that STAT3 binds to the promoters of the G6Pase, PEPCK, and suppressor of cytokine signaling (SOCS)3 genes, and its recruitment increases at the G6Pase and SOCS3 promoters with IL-6 treatment. Whereas persistent recruitment of RNA polymerase II is seen on the SOCS3 promoter, consistent with its induction by IL-6, a decrease in polymerase II recruitment and histone H4 acetylation is seen at the G6Pase promoter with IL-6 treatment. Thus STAT3 mediates negative regulation of hepatic gluconeogenic gene expression in vivo by interacting with regulatory regions of these genes.
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PMID:STAT3 targets the regulatory regions of gluconeogenic genes in vivo. 1926 44

Hepatic gluconeogenesis is a major contributing factor to hyperglycemia in the fasting and postprandial states in type 2 diabetes mellitus (T2DM). Because Sirtuin 1 (SirT1) induces hepatic gluconeogenesis during fasting through the induction of phosphoenolpyruvate carboxylase kinase (PEPCK), fructose-1,6-bisphosphatase (FBPase), and glucose-6-phosphatase (G6Pase) gene transcription, we hypothesized that reducing SirT1, by using an antisense oligonucleotide (ASO), would decrease fasting hyperglycemia in a rat model of T2DM. SirT1 ASO lowered both fasting glucose concentration and hepatic glucose production in the T2DM rat model. Whole body insulin sensitivity was also increased in the SirT1 ASO treated rats as reflected by a 25% increase in the glucose infusion rate required to maintain euglycemia during the hyperinsulinemic-euglycemic clamp and could entirely be attributed to increased suppression of hepatic glucose production by insulin. The reduction in basal and clamped rates of glucose production could in turn be attributed to decreased expression of PEPCK, FBPase, and G6Pase due to increased acetylation of signal transducer and activator of transcription 3 (STAT3), forkhead box O1 (FOXO1), and peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha), known substrates of SirT1. In addition to the effects on glucose metabolism, SirT1 ASO decreased plasma total cholesterol, which was attributed to increased cholesterol uptake and export from the liver. These results indicate that inhibition of hepatic SirT1 may be an attractive approach for treatment of T2DM.
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PMID:SirT1 knockdown in liver decreases basal hepatic glucose production and increases hepatic insulin responsiveness in diabetic rats. 1954 53

The biguanide derivative metformin is a potent anti-diabetic drug widely used in the treatment of type 2 diabetes mellitus. Its major effect on glucose metabolism consists in the inhibition of hepatic glucose production. Since the mechanisms of metformin action are only partially understood at the molecular level, we studied the regulation of the gene promoter activity of glucose-6-phosphatase (G6Pase), the central hepatic gluconeogenic enzyme, by this drug. We have found that both metformin and insulin inhibit the basal and dexamethasone/cAMP-stimulated G6Pase promoter activity in hepatoma cells. Since one of the pharmacological targets of metformin is AMP-activated protein kinase (AMPK) and activation of AMPK is known to inhibit hepatic glucose production by the suppression of G6Pase gene transcription, we studied the effect of AMPK in this context. Under nonstimulated conditions, the inhibitory effect of both insulin and metformin was partially counteracted to a similar extent by treatment with compound C, a specific inhibitor of AMPK. In contrast, under conditions of stimulation with dexamethasone and cAMP, treatment with compound C reversed the inhibitory effect of metformin on G6Pase promoter activity to a similar extent as compared to nonstimulated conditions, whereas the effect of insulin was almost resistant to treatment with the AMPK-antagonist. These data indicate a differential AMPK-dependent regulation of G6Pase gene expression by insulin and metformin under basal and dexamethasone/cAMP-stimulated conditions.
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PMID:Regulation of glucose-6-phosphatase gene expression by insulin and metformin. 1957 80

Metformin is widely used as a hypoglycemic agent for the treatment of type 2 diabetes. Both metformin and rotenone, an inhibitor of respiratory chain complex I, suppressed glucose-6-phosphatase (G6pc), a rate limiting enzyme of liver glucose production, mRNA expression in a rat hepatoma cell line accompanied by a reduction of intracellular ATP concentration and an activation of AMP-activated protein kinase (AMPK). When yeast NADH-quinone oxidoreductase 1 (NDI1) gene was introduced into the cells, neither inhibition of ATP synthesis nor activation of AMPK was induced by these agents. Interestingly, in contrast to rotenone treatment, G6pc mRNA down-regulation was observed in the NDI1 expressing cells after metformin treatment. Since NDI1 can functionally complement the complex I under the presence of metformin or rotenone, our results indicate that metformin induces down-regulation of G6pc expression through an inhibition of complex I and an activation of AMPK-independent mechanism.
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PMID:Metformin suppresses glucose-6-phosphatase expression by a complex I inhibition and AMPK activation-independent mechanism. 1966 96

The unfolded protein response (UPR) or endoplasmic reticulum (ER) stress response is a physiological process enabling cells to cope with altered protein synthesis demands. However, under conditions of obesity, prolonged activation of the UPR has been shown to have deteriorating effects on different metabolic pathways. Here we identify Bax inhibitor-1 (BI-1), an evolutionary conserved ER-membrane protein, as a novel modulator of the obesity-associated alteration of the UPR. BI-1 partially inhibits the UPR by interacting with IRE1alpha and inhibiting IRE1alpha endonuclease activity as seen on the splicing of the transcription factor Xbp-1. Because we observed a down-regulation of BI-1 expression in liver and muscle of genetically obese ob/ob and db/db mice as well as in mice with diet-induced obesity in vivo, we investigated the effect of restoring BI-1 expression on metabolic processes in these mice. Importantly, BI-1 overexpression by adenoviral gene transfer dramatically improved glucose metabolism in both standard diet-fed mice as well as in mice with diet-induced obesity and, critically, reversed hyperglycemia in db/db mice. This improvement in whole body glucose metabolism and insulin sensitivity was due to dramatically reduced gluconeogenesis as shown by reduction of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase expression. Taken together, these results identify BI-1 as a critical regulator of ER stress responses in the development of obesity-associated insulin resistance and provide proof of concept evidence that gene transfer-mediated elevations in hepatic BI-1 may represent a promising approach for the treatment of type 2 diabetes.
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PMID:Hepatic Bax inhibitor-1 inhibits IRE1alpha and protects from obesity-associated insulin resistance and glucose intolerance. 1999 3

Inactive cortisone is converted to active cortisol within the liver by 11 beta-hydroxysteroid dehydrogenase-1 (11 beta-HSD1), and impaired regulation of this process may be related to increased hepatic glucose production (HGP) in individuals with type 2 diabetes. The primary aim of this study was to investigate the effect of acute 11 beta-HSD1 inhibition on HGP and fat metabolism during insulin deficiency. Sixteen conscious, 42-h-fasted, lean, healthy dogs were studied. Somatostatin was infused to create insulin deficiency, and the animals were treated with a specific 11 beta-HSD1 inhibitor (compound 531) or placebo for 5 h. 11 beta-HSD1 inhibition completely suppressed hepatic cortisol production, and this attenuated the increase in HGP that occurred during insulin deficiency. PEPCK and glucose-6-phosphatase expression were decreased when 11 beta-HSD1 was inhibited, but gluconeogenic flux was unchanged, implying an effect on glycogenolysis. Since inhibition of hepatic cortisol production reduces HGP during insulin deficiency, 11 beta-HSD1 is a potential therapeutic target for the treatment of excess glucose production that occurs in diabetes.
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PMID:Effect of 11 beta-hydroxysteroid dehydrogenase-1 inhibition on hepatic glucose metabolism in the conscious dog. 2015 54

Trigonelline (TRG) and nicotinic acid (NA), in which the former but not the latter improved the blood glucose level in the oral glucose tolerance test (OGTT) in Goto-Kakizaki (GK) rats were tested for anti-diabetic effects in mellitus models of KK-A(y) obese mice that had type 2 diabetes. Blood glucose level in OGTT carried out on day 22-23 was lowered after feeding in mice fed TRG and NA than that of the control mice not fed these compounds, indicating that both TRG and NA have sufficient activity to improve glucose tolerance in diabetes with obesity. The serum insulin levels at fasting showed significantly lower levels in mice fed TRG, and a lower tendency in mice fed NA, compared with the control mice. The triglyceride (TG) levels in the liver and adipose tissue in mice fed TRG and NA showed lower values or a lower tendency than those of the control mice, indicating that TRG and NA were also effective to improve the changes in lipid levels accompanied with diabetes. Higher values or a higher tendency of the glucokinase (GLK)/glucose-6-phosphatase (G6Pase) ratio in the liver and lower levels of the serum tumor necrosis factor (TNF)-alpha in the TRG- and NA-fed mice, compared to the control mice, suggested that the regulation of GLK and G6Pase, and TNF-alpha production by TRG and NA are closely related in suppressing the progression of diabetes in the KK-A(y) mice.
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PMID:Anti-diabetic effect of trigonelline and nicotinic acid, on KK-A(y) mice. 2042 1

Insulin resistance has been implicated in the pathogenesis of type 2 diabetes. High fat diets cause insulin resistance. Both metformin and pioglitazone are considered "insulin sensitizers" and used as antihyperglycemic agents for type 2 diabetes treatment. The aim of this study is to Compare pioglitazone and metformin effects on carbohydrate metabolism and insulin sensitivity in diabetic and glucose intolerant rats on high fat diet. Male albino rats were randomized to seven groups. The 1st group received high carbohydrate diet (control). The 2nd, 3rd and 4th groups received high sunflower oil diets for 6 weeks and either left untreated, or given pioglitazone or metformin during the last 3 weeks. The 5th, 6th, and 7th groups were made diabetic by STZ injection on day 15 of the 6 weeks-high fat diet regimen. They were either left untreated, or given pioglitazone or metformin during the last 3 weeks. High-fat diet induced glucose intolerance; represented by increase of serum glucose associated with increase in liver glucose-6-phosphatase and decreases in liver glucose-6-phosphate dehydrogenase and glucokinase activities. No significant differences were observed between pioglitazone and metformin. In diabetic rats, both pioglitazone and metformin decreased elevated serum glucose by approximately 30%. Only metformin increased hepatic glycogen, and normalized glucose-6-phosphatase activity. On the other hand, pioglitazone normalized elevated renal glycogen content and increased glucose-6-phosphate dehydrogenase activity. High sunflower oil diet impaired glucose tolerance. Pioglitazone and metformin had comparable effects on estimates of carbohydrate metabolism and insulin sensitivity in high-fat fed rats, but different effects in diabetic rats.
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PMID:Pioglitazone versus metformin in two rat models of glucose intolerance and diabetes. 2056 45


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