Oral Glucose Tolerance Test Study Research Articles

Mice Lacking Mrs2 Magnesium Transporter are Hypophagic and Thin When Maintained on a High-Fat Diet.

Genes regulating body fat are shared with high fidelity by mice and humans, indicating that mouse knockout (KO) phenotyping might identify valuable antiobesity drug targets. Male Mrs2 magnesium transporter (Mrs2) KO mice were recently reported as thin when fed a high-fat diet (HFD). They also exhibited increased energy expenditure (EE)/body weight and had beiged adipocytes that, along with isolated hepatocytes, demonstrated increased oxygen consumption, suggesting that increased EE drove the thin phenotype. Here we provide our data on these and additional assays in Mrs2 KO mice. We generated Mrs2 KO mice by homologous recombination. HFD-fed male and female Mrs2 KO mice had significantly less body fat, measured by quantitative magnetic resonance, than wild-type (WT) littermates. HFD-fed Mrs2 KO mice did not demonstrate increased EE by indirect calorimetry and could not maintain body temperature at 4 °C, consistent with their decreased brown adipose tissue stores but despite increased beige white adipose tissue. Instead, when provided a choice between HFD and low-fat diet (LFD), Mrs2 KO mice showed a significant 15% decrease in total energy intake resulting from significantly lower HFD intake that offset numerically increased LFD intake. Food restriction studies performed using WT mice suggested that this decrease in energy intake could explain the loss of body fat. Oral glucose tolerance test studies revealed significantly improved insulin sensitivity in Mrs2 KO mice. We conclude that HFD-fed Mrs2 KO mice are thin with improved insulin sensitivity, and that this favorable metabolic phenotype is driven by hypophagia. Further evaluation is warranted to determine the suitability of MRS2 as a drug target for antiobesity therapeutics.

1302-P: Predicting Insulin Time-Course Profiles for Early Prediabetes Interception Using a Mechanistic Mathematical Model

Early detection of prediabetes using blood glucose remains difficult as individuals often present with slight elevations or even normoglycaemia. However, their insulin profiles usually show marked elevations, suggesting that insulin is a more sensitive biomarker for prediabetes. We developed a mechanistic whole-body model that can predict an individual’s insulin time-course and insulin sensitivity from a given glucose time-course. The model describes the absorption, distribution, metabolism and excretion of glucose and the relevant hormones, while various homeostatic processes such as insulin secretion were dynamically represented by sub-models. Matched glucose and insulin data were obtained from 7 oral glucose tolerance test studies. Model predictions of insulin time-course using glucose data as inputs were compared with observed data for validation (Fig 1). Both population and individual simulation results indicated robust prediction of insulin profiles and demonstrate that it is possible to utilize glucose data (easy to obtain) to predict insulin data (difficult to obtain) for prediabetes screening. Disclosure K.Hor cheng: None. J.C.Y.Chan: None.

Significance of pancreatic duodenal homeobox-1 (PDX-1) genetic polymorphism in insulin secretion in Japanese patients with type 2 diabetes

IntroductionPancreatic and duodenal homeobox factor-1 (PDX-1) is an imperative gene for insulin secretion in maturity-onset diabetes of the young 4. PDX-1 gene polymorphism was associated with lower first-phase insulin secretion...

Maturity Onset Diabetes of the Young Masquerading as New Onset Diabetes Mellitus Type 1

Introduction:/background: Maturity-onset diabetes of the young (MODY) is a heterogeneous group of monogenic disorders with autosomal dominant mode of inheritance. Mutation in hepatocyte nuclear factor-1β (HNF-1β) gene results in an error of embryonic development of pancreas and nephron, leading to MODY type 5. MODY 5 accounts for 1% of maturity-onset diabetes of the young. It has peak incidence in adolescence/early adulthood, and is associated with renal pathology. Clinical Case: A 15-year boy with history of hypertension and Hashimoto thyroiditis with normal thyroid function was referred for Hb A1C of 6.7% (< 6.4%). Physical exam was remarkable for normal weight at 64%, normal BMI at 83%, absence of thyromegaly or acanthosis nigricans. Diabetes was confirmed by 2 hour Oral Glucose Tolerance Test study (baseline glucose 154 mg/dL (<126 mg/dL), 2 hour glucose 384 mg/dL (<140 mg/dL)). Small doses of insulin (total daily dose 0.1 units/kg/day) resulted in good glucose control. Further labs were significant for weakly positive TTG and GAD antibodies (tTG Ab IgA 55.5 U/mL (<4.0 U/mL), GAD-65 Ab 0.05 nmol/L (< 0.02 nmol/L)), positive TPO (0.0 - 34.9 IU/mL) and detectable ATA antibodies 45.8 IU/mL (0.0 - 40.0 IU/mL), C-peptide 2.9 ng/mL (0.9–7.1 ng/mL). Islet cell, Insulin and Zinc transporter 8 antibodies were negative. Over the next few months he was weaned off insulin and subsequently he had a high insulin of 29.43 uU/mL (3.0 - 17.0 uU/mL) with glucose level of 169 mg/dL. Renal US was performed as part of the work up for hypertension and revealed a small right calculus with no hydronephrosis and a small 8-mm cortical cyst in the right kidney. Urinalysis showed microalbuminuria. Upper GI endoscopy and colonoscopy with biopsy ruled out celiac disease. Presumptive diagnosis of MODY was entertained despite positive TPO, ATA, TTG and GAD antibodies suggesting autoimmune endocrinopathies. His Hb A1C levels were in the range of 5.7 to 6 % during the 15 months of follow up. Genetic testing for MODY resulted in heterozygous deletion of exons 1–9 of the HNF1B gene consistent with MODY5. Conclusion: This is a case of MODY 5 with weakly positive GAD 65 antibodies that was initially misdiagnosed as type 1 diabetes. The presence of weakly positive antibodies should not preclude a work up for MODY in a patient who does not have the clinical features of classic type 1 DM.

Enhanced glycemic control, pancreas protective, antioxidant and hepatoprotective effects by umbelliferon-α-D-glucopyranosyl-(2(I) → 1(II))-α-D-glucopyranoside in streptozotocin induced diabetic rats.

ObjectiveThe objective of the present study was to evaluate the effect of umbelliferon-α-D-glucopyranosyl-(2I → 1II)-α-D-glucopyranoside (UFD) from Aegle marmelos Corr. on serum glucose, lipid profile and free radical scavenging activity in normal and STZ (streptozotocin) induced diabetic rats.Materials and methodsDiabetes was induced by single interperitoneal injecting of streptozotocin (60 mg/kg, i.p.) in the rats. All the rats were divided into following groups; I - nondiabeteic, II - nondiabetic + UFD (40 mg/kg, p.o.), III - diabetic control, IV - UFD (10 mg/kg, p.o.), V - UFD (20 mg/kg, p.o.), VI - UFD (40 mg/kg) and VII - glibenclamide (10 mg/kg, p.o.). Serum glucose level and body weight were determined periodically. Biochemical parameter, antioxidant enzyme and histopathology study were performed on the day 28. Oral glucose tolerance test study was performed to identify the glucose utilization capacity.ResultsAll the doses of UFD and glibenclamide decrease the level of serum glucose, glycated hemoglobin, glucose-6-phosphatase, fructose-1-6-biphosphate and increased the level of plasma insulin, hexokinase. The UFD doses also showed effects on antioxidant enzymes viz. superoxide dismutase, catalase and glutathione peroxidase which were significantly increased and the level of malonaldehyde was markedly decreased. Histologically study, focal necrosis, deposition of fats, increased the size of the intercalated disc were observed in the diabetic rat liver, kidney, heart and pancreas but was less obvious in treated groups. The mechanism of action of the UFD emerges to be due to increase the activity of antioxidant enzyme and secretion of pancreatic insulin.ConclusionReduction in the FBG (fasting blood glucose), glycated hemoglobin, glucose-6-phosphatase, fructose-1-6-biphosphate, superoxide dismutase, catalase, glutathione peroxides, cholesterol, triglyceride, LDL, VLDL levels and improvement in the level of the plasma insulin, hexokinase, HDL was observed by the UFD treated rats. The result indicates that UFD has anti-diabetic activity along with anti hyperlipidemic and antioxidant efficacy and provides a scientific rationale to be used as an Anti-diabetic agent.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-639) contains supplementary material, which is available to authorized users.

Ghrelin and Leptin Response to Oral Glucose Challenge Among Antipsychotic Drug-Treated Children

We investigated ghrelin, leptin, glucose, and insulin response to an oral glucose tolerance test among children receiving antipsychotics. Hormone concentrations were assayed at fasting, 30, 60, and 120 minutes. The sample was composed of 9 obese (defined as at or above the 95th percentile for age) and 10 overweight/normal children (defined as less than the 95th percentile in weight) based on National Institutes of Health criteria. Ages of the obese (10.7 +/- 3.4 years) and the overweight/normal (13.1 +/- 1.6 years) did not differ. Leptin was significantly higher among the obese group and did not change consequent to glucose. Ghrelin did not differ between the groups, and when the values were combined, ghrelin decreased at 30 minutes and approached fasting concentrations at 120 minutes. To further explore our data, we constituted separate groups based upon z score changes. When weight gain defined as an increase in z score (X = 0.4), the nongainers showed leptin concentrations to decrease over time. Findings encourage further oral glucose tolerance test studies to explain the leptin response to weight gain seen among children receiving antipsychotic medication.

Adipose tissue metabolites and insulin resistance in nondiabetic Asian Indian men.

Obesity-related insulin resistance is associated with changes in adipose tissue release of leptin, adiponectin, and nonesterified fatty acids (NEFAs). We have previously described that persons originating from the Indian subcontinent (Asian Indians) manifest excessive insulin resistance even in the absence of obesity. Therefore, in this study, we tested the hypothesis that nondiabetic, insulin-resistant Asian Indians differ from less insulin-resistant Caucasians of similar age and body composition in adipose tissue production of leptin and adiponectin, and in suppression of plasma NEFA concentrations during hyperinsulinemia. Seventy-nine Asian Indian men were compared with 61 Caucasian men. Higher plasma NEFAs and leptin in Asian Indians (P < 0.0001 and P = 0.003 for NEFAs and leptin, respectively) and lower plasma concentrations of adiponectin (P = 0.009) were not explained by body fat content and distribution. Oral glucose tolerance test studies revealed that Caucasian men had greater suppression of plasma NEFAs than Asian Indian men. We conclude that plasma concentrations of the adipose tissue metabolites leptin and NEFAs are higher and that of adiponectin is lower in insulin-resistant Asian Indians compared with more insulin-sensitive Caucasians. These differences may contribute to the excessive prevalence of type 2 diabetes and cardiovascular disease in nonobese Asian Indians.

Effect of eicosapentaenoic acid ethyl ester v. oleic acid-rich safflower oil on insulin resistance in type 2 diabetic model rats with hypertriacylglycerolaemia.

The purpose of the present study was to test whether hyperlipidaemia and insulin resistance in type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats can be improved by dietary supplementation with purified eicosapentaenoic acid (EPA) or oleic acid (OA). Male OLETF rats were fed powdered chow (510 g fat/kg) alone (n 8) or chow supplemented with 10 g EPA- (n 8) or OA- (n 8) rich oil/kg per d from 5 weeks until 30 weeks of age. An oral glucose tolerance test and hyperinsulinaemic euglycaemic clamp was performed at 25 and 30 weeks of age. EPA supplementation resulted in significantly (P<0.05) reduced plasma lipids, hepatic triacylglycerols, and abdominal fat deposits, and more efficient in vivo glucose disposal compared with OA supplementation and no supplementation. OA supplementation was associated with significantly increased insulin response to oral glucose compared with EPA supplementation and no supplementation. Inverse correlation was noted between glucose uptake and plasma triacylglycerol levels (r -086, P<0.001) and abdominal fat volume (r -0.80, P<0.001). The result of oral glucose tolerance test study showed that the rats fed EPA tended to improve glucose intolerance, although this was not statistically significant. Levels of plasma insulin at 60 min after glucose was significantly increased in rats fed OA compared with the other two groups. The results indicate that long-term feeding of EPA might be effective in preventing insulin resistance in diabetes-prone rats, at least in part, due to improving hypertriacylglycerolaemia.