1785-P: Mice with Muscle-Specific Insulin Receptor Overexpression Are Protected from Diet-Induced Obesity and Glucose Intolerance but Develop Post-Receptor Insulin Resistance

Obesity increases the risk of many cancers in both males and females. This study describes a link between obesity, obesity-associated metabolic alterations, and the risk of developing cancer in male and female mice. The goal of this study was to evaluate the relationship between gender and obesity and to determine the role of estrogen status in obese females and its effect on tumor growth. We examined the susceptibility of C57BL/6 mice to diet-induced obesity, insulin resistance/glucose intolerance, and tumors. Mice were injected sc with one of two tumorigenic cell lines, Lewis lung carcinoma, or mouse colon 38-adenocarcinoma. Results show that tumor growth rate was increased in obese mice vs. control mice irrespective of the tumor cell type. To investigate the effect of estrogen status on tumor development in obese females, we compared metabolic parameters and tumor growth in ovariectomized (ovx) and intact obese female mice. Obese ovx female mice developed insulin resistance and glucose intolerance similar to that observed in obese males. Our results demonstrate that body adiposity increased in ovx females irrespective of the diet administered and that tumor growth correlated positively with body adiposity. Overall, these data point to more rapid tumor growth in obese mice and suggest that endogenous sex steroids, together with diet, affect adiposity, insulin sensitivity, and tumor growth in female mice.

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Reduced insulin receptor signaling in the obese spontaneously hypertensive Koletsky rat

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1997.273.5.e1014 ◽

1997 ◽

Vol 273 (5) ◽

pp. E1014-E1023 ◽

Cited By ~ 17

Author(s):

Jacob E. Friedman ◽

Tatsuya Ishizuka ◽

Sha Liu ◽

Craig J. Farrell ◽

David Bedol ◽

...

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Insulin Receptor ◽

Tyrosine Phosphorylation ◽

Glucose Intolerance ◽

Leptin Receptor ◽

Spontaneously Hypertensive Rat ◽

Regulatory Subunit ◽

Oral Glucose ◽

Spontaneously Hypertensive

Insulin resistance is associated with both obesity and hypertension. However, the cellular mechanisms of insulin resistance in genetic models of obese-hypertension have not been identified. The objective of the present study was to investigate the effects of genetic obesity on a background of inherited hypertension on initial components of the insulin signal transduction pathway and glucose transport in skeletal muscle and liver. Oral glucose tolerance testing in SHROB demonstrated a sustained postchallenge elevation in plasma glucose at 180 and 240 min compared with lean spontaneously hypertensive rat (SHR) littermates, which is suggestive of glucose intolerance. Fasting plasma insulin levels were elevated 18-fold in SHROB. The rate of insulin-stimulated 3- O-methylglucose transport was reduced 68% in isolated epitrochlearis muscles from the SHROB compared with SHR. Insulin-stimulated tyrosine phosphorylation of the insulin receptor β-subunit and insulin receptor substrate-1 (IRS-1) in intact skeletal muscle of SHROB was reduced by 36 and 23%, respectively, compared with SHR, due primarily to 32 and 60% decreases in insulin receptor and IRS-1 protein expression, respectively. The amounts of p85α regulatory subunit of phosphatidylinositol-3-kinase and GLUT-4 protein were reduced by 28 and 25% in SHROB muscle compared with SHR. In the liver of SHROB, the effect of insulin on tyrosine phosphorylation of IRS-1 was not changed, but insulin receptor phosphorylation was decreased by 41%, compared with SHR, due to a 30% reduction in insulin receptor levels. Our observations suggest that the leptin receptor mutation fak imposed on a hypertensive background results in extreme hyperinsulinemia, glucose intolerance, and decreased expression of postreceptor insulin signaling proteins in skeletal muscle. Despite these changes, hypertension is not exacerbated in SHROB compared with SHR, suggesting these metabolic abnormalities may not contribute to hypertension in this model of Syndrome X.

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Tissue-specific insulin resistance in mice with mutations in the insulin receptor, IRS-1, and IRS-2

Journal of Clinical Investigation ◽

10.1172/jci7917 ◽

2000 ◽

Vol 105 (2) ◽

pp. 199-205 ◽

Cited By ~ 353

Author(s):

Yoshiaki Kido ◽

Deborah J. Burks ◽

Dominic Withers ◽

Jens C. Bruning ◽

C. Ronald Kahn ◽

...

Keyword(s):

Insulin Resistance ◽

Insulin Receptor ◽

Tissue Specific ◽

Specific Insulin

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Mo1951 Chronic Intestinal Electrical Stimulation Improves Glucose Intolerance and Insulin Resistance in Diet-Induced Obesity Rats

Gastroenterology ◽

10.1016/s0016-5085(16)32793-7 ◽

2016 ◽

Vol 150 (4) ◽

pp. S825-S826

Author(s):

Shiying Li ◽

Weijian Zhu ◽

Jiande Chen

Keyword(s):

Insulin Resistance ◽

Electrical Stimulation ◽

Glucose Intolerance ◽

Diet Induced Obesity ◽

Intestinal Electrical Stimulation

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Freeze-dried jaboticaba peel powder improves insulin sensitivity in high-fat-fed mice

British Journal Of Nutrition ◽

10.1017/s0007114512005090 ◽

2013 ◽

Vol 110 (3) ◽

pp. 447-455 ◽

Cited By ~ 35

Author(s):

Nathalia R. V. Dragano ◽

Anne y Castro Marques ◽

Dennys E. C. Cintra ◽

Carina Solon ◽

Joseane Morari ◽

...

Keyword(s):

Insulin Resistance ◽

Insulin Receptor ◽

Tolerance Test ◽

Protective Role ◽

High Fat ◽

Protein Levels ◽

Diet Induced Obesity ◽

Forkhead Box ◽

Insulin Tolerance ◽

Freeze Dried

The peel of the native Brazilian fruit jaboticaba is rich in anthocyanins, which are known for their anti-obesity effects in animal models. The aim of the present study was to evaluate the effects of freeze-dried jaboticaba peel powder (FDJPP) on a number of metabolic parameters in a model of diet-induced obesity. Mice (n 8 per group) were initially fed on a high-fat diet (HFD, 35 % w/w) for 4 weeks and then switched to a HFD supplemented with FDJPP (1, 2 or 4 % w/w) for an additional 6 weeks. Energy intake, weight loss, glucose tolerance, insulin resistance and lipid profile were determined, and the results were evaluated using ANOVA and Tukey's tests. The FDJPP exerted no protective effect on HFD-induced weight gain, hyperleptinaemia and glucose intolerance. However, the supplementation was effective to reduce insulin resistance, as evidenced in the insulin tolerance test, and subsequently confirmed by improved signal transduction through the insulin receptor/insulin receptor substrate-1/Akt/forkhead box protein pathway and by the attenuation of HFD-induced inflammation in the liver, verified by lower expressions of IL-1β and IL-6 and decreased phosphorylated IκB-α protein levels in all jaboticaba-treated mice. These results suggest that FDJPP may exert a protective role against obesity-associated insulin resistance.

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Metformin improves hepatic IRS2/PI3K/Akt signaling in insulin-resistant rats of NASH and cirrhosis

Journal of Endocrinology ◽

10.1530/joe-15-0409 ◽

2016 ◽

Vol 229 (2) ◽

pp. 133-144 ◽

Cited By ~ 49

Author(s):

Hong Xu ◽

Yang Zhou ◽

Yongxia Liu ◽

Jian Ping ◽

Qiyang Shou ◽

...

Keyword(s):

Insulin Resistance ◽

Liver Function ◽

Insulin Receptor ◽

Glucose Intolerance ◽

Glycogen Synthase ◽

Glycogen Synthesis ◽

Akt Signaling ◽

Hepatic Glycogen ◽

Impaired Liver Function ◽

Insulin Resistant

Nonalcoholic fatty liver disease and cirrhosis are strongly associated with insulin resistance and glucose intolerance. To date, the influence of metformin on glycogen synthesis in the liver is controversial. Limited studies have evaluated the effect of metformin on hepatic insulin signaling pathwayin vivo. In this study, an insulin-resistant rat model of nonalcoholic steatohepatitis and cirrhosis was developed by high-fat and high-sucrose diet feeding in combination with subcutaneous injection of carbon tetrachloride. Liver tissues of the model rats were featured with severe steatosis and cirrhosis, accompanied by impaired liver function and antioxidant capacity. The glucose tolerance was impaired, and the index of insulin resistance was increased significantly compared with the control. The content of hepatic glycogen was dramatically decreased. The expression of insulin receptor β (IRβ); phosphorylations of IRβ, insulin receptor substrate 2 (IRS2), and Akt; and activities of phosphatidylinositol 3-kinase (PI3K) and glycogen synthase (GS) in the liver were significantly decreased, whereas the activities of glycogen synthase kinase 3α (GSK3α) and glycogen phosphorylase a (GPa) were increased. Metformin treatment remarkably improved liver function, alleviated lipid peroxidation and histological damages of the liver, and ameliorated glucose intolerance and insulin resistance. Metfromin also significantly upregulated the expression of IRβ; increased the phosphorylations of IRβ, IRS2, and Akt; increased the activities of PI3K and GS; and decreased GSK3α and GPa activities. In conclusion, our study suggests that metformin upregulates IRβ expression and the downstream IRS2/PI3K/Akt signaling transduction, therefore, to increase hepatic glycogen storage and improve insulin resistance. These actions may be attributed to the improved liver histological alterations by metformin.

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