scholarly journals Studies of the Impact of a Liver Glucokinase Promoter Variant on Glucose Tolerance and Insulin Sensitivity Index1

1997 ◽  
Vol 82 (6) ◽  
pp. 1786-1789
Author(s):  
Søren A. Urhammer ◽  
Torben Hansen ◽  
Liselotte Brix Jensen ◽  
Jesper O. Clausen ◽  
Lars Hansen ◽  
...  

Abstract Because a frequently occurring nucleotide substitution at position− 258 in the liver glucokinase promoter has been reported to be associated with impaired promoter activity, we have examined in Danish Caucasians whether this variant is associated with alterations in glucose tolerance and/or the insulin sensitivity index (Si). Among 246 Danish Caucasian patients with noninsulin-dependent diabetes mellitus, the allelic frequency of the −258 promoter variant was 15.2% (95% confidence interval: 12.0–18.4%) vs. 16.5% (13.2–19.8%) among 242 matched control subjects. In the control group, the glucokinase variant was not related to serum insulin or plasma glucose levels before or during an oral glucose tolerance test. Neither was the gene variant among 380 young, healthy subjects associated with altered Si or altered insulin secretion after an iv glucose load. We conclude that in Danish Caucasians, the −258 glucokinase promoter variant has no impact on glucose tolerance, whole-body Si, or insulin secretion.

Author(s):  
Nicole Sheanon ◽  
Deborah Elder ◽  
Jane Khoury ◽  
Lori Casnellie ◽  
Iris Gutmark-Little ◽  
...  

Intro: Adult women with Turner syndrome (TS) have a high prevalence of diabetes and β-cell dysfunction that increases morbidity and mortality, but, it is unknown if there is β-cell dysfunction present in youth with TS. This study aimed to determine the prevalence of β-cell dysfunction in youth with TS and the impact of traditional therapies on insulin sensitivity and insulin secretion. Methods: Cross-sectional, observational study recruited 60 girls with TS and 60 healthy controls (HC) matched on pubertal status. Each subject had a history, physical exam and oral glucose tolerance test (OGTT). Oral glucose and c-peptide minimal modeling was used to determine β-cell function. Results: Twenty-one TS girls (35%) met criteria for pre-diabetes. Impaired fasting glucose (IFG) was present in 18% of girls with TS and 2% HC (p-value = 0.0003). Impaired glucose tolerance (IGT) was present in 23% of TS girls and 0% HC (p-value < 0.001). The HbA1c was not different between TS and HC (median 5%, p= 0.42). Youth with TS had significant reductions in insulin sensitivity (SI), β-cell responsivity (Φ), and disposition index (DI) compared to HC. These differences remained significant when controlling for BMI z-score (p-values: 0.0006, 0.002, <0.0001 for SI, Φtotal, DI, respectively). Conclusions: β-cell dysfunction is present in youth with TS compared to controls. The presence of both reduced insulin secretion and insulin sensitivity suggest a unique TS-related glycemic phenotype. Based on the data from this study, we strongly suggest that providers employ serial OGTT to screen for glucose abnormalities in TS youth.


2017 ◽  
Vol 29 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Kevin R. Short ◽  
April M. Teague ◽  
Jake C. Klein ◽  
Elizabeth Malm-Buatsi ◽  
Dominic Frimberger

Purpose:Whole body or leg exercise before a meal can increase insulin sensitivity, but it is unclear whether the same can occur with upper body exercise since a smaller muscle mass is activated. We measured the impact of a single session of handcycle exercise on glucose tolerance and insulin sensitivity.Methods:Nonambulatory (Non-Amb) adolescents with spina bifida or cerebral palsy (4F/3M), or ambulatory peers (Control, 4F/7M) completed 2 glucose tolerance tests on separate days, preceded by either rest or a 35-min bout of moderate-to-vigorous intermittent handcycle exercise.Results:The Non-Amb group had higher body fat (mean ± SD: 38 ± 12%, Control: 24 ± 9, p = .041) but similar VO2peak (17.7 ± 6.1 ml/kg/min, Control: 21.1 ± 7.9). Fasting glucose and insulin were normal for all participants. Compared with the rest trial, exercise resulted in a reduction in glucose area under the curve (11%, p = .008) without a significant group x trial interaction and no difference in the magnitude of change between groups. Insulin sensitivity was increased 16% (p = .028) by exercise in the Control group but was not significantly changed in the Non-Amb group.Conclusion:A single bout of handcycle exercise improves glucose tolerance in adolescents with and without mobility limitations and could therefore help maintain or improve metabolic health.


2015 ◽  
Vol 172 (4) ◽  
pp. 423-432 ◽  
Author(s):  
Christian Herder ◽  
D Margriet Ouwens ◽  
Maren Carstensen ◽  
Bernd Kowall ◽  
Cornelia Huth ◽  
...  

ObjectiveReduced circulating omentin levels have been reported in obesity and type 2 diabetes, but data were mostly derived from univariate analyses in small study samples. This study aimed to investigate the relationship between omentin, abnormal glucose tolerance and related metabolic factors in a large population-based cross-sectional study.Design and methodsSerum omentin was measured by ELISA in 1092 participants of the German KORA F4 survey (2006–2008). Associations between omentin serum levels, glucose tolerance (assessed with an oral glucose tolerance test) and diabetes-related factors were estimated using logistic and linear regression models respectively.ResultsSerum levels of omentin were not related to categories of glucose tolerance. However, serum omentin was positively associated with whole-body insulin sensitivity index (ISI (composite)) and HDL cholesterol and showed inverse associations with 2-h post-load glucose, fasting insulin, homeostasis model assessment-estimated insulin resistance, BMI and triglycerides (all P≤0.03 after adjustment for age, sex and lifestyle factors). Further adjustment for BMI and/or serum lipids attenuated the associations with parameters of glucose metabolism, whereas adjustment for serum adiponectin virtually abolished all aforementioned associations. In contrast, adjustment for omentin had no effect on the positive association between adiponectin levels and ISI (composite).ConclusionsThe data from this large population-based cohort show that circulating omentin levels are associated with insulin sensitivity. Our observations further suggest that omentin acts via upregulation of adiponectin, which in turn affects lipid metabolism and thereby also indirectly enhances insulin sensitivity, but mechanistic studies are required to corroborate this hypothesis.


2020 ◽  
Vol 125 (2) ◽  
pp. 147-160
Author(s):  
Mariana O. C. Coelho ◽  
Alistair J. Monteyne ◽  
Marlou L. Dirks ◽  
Tim J. A. Finnigan ◽  
Francis B. Stephens ◽  
...  

AbstractMycoprotein consumption has been shown to improve acute postprandial glycaemic control and decrease circulating cholesterol concentrations. We investigated the impact of incorporating mycoprotein into the diet on insulin sensitivity (IS), glycaemic control and plasma lipoprotein composition. Twenty healthy adults participated in a randomised, parallel-group trial in which they consumed a 7 d fully controlled diet where lunch and dinner contained either meat/fish (control group, CON) or mycoprotein (MYC) as the primary source of dietary protein. Oral glucose tolerance tests were performed pre- and post-intervention, and 24 h continuous blood glucose monitoring was applied throughout. Fasting plasma samples were obtained pre- and post-intervention and were analysed using quantitative, targeted NMR-based metabonomics. There were no changes within or between groups in blood glucose or serum insulin responses, nor in IS or 24 h glycaemic profiles. No differences between groups were found for 171 of the 224 metabonomic targets. Forty-five lipid concentrations of different lipoprotein fractions (VLDL, LDL, intermediate-density lipoprotein and HDL) remained unchanged in CON but showed a coordinated decrease (7–27 %; all P < 0·05) in MYC. Total plasma cholesterol, free cholesterol, LDL-cholesterol, HDL2-cholesterol, DHA and n-3 fatty acids decreased to a larger degree in MYC (14–19 %) compared with CON (3–11 %; P < 0·05). Substituting meat/fish for mycoprotein twice daily for 1 week did not modulate whole-body IS or glycaemic control but resulted in changes to plasma lipid composition, the latter primarily consisting of a coordinated reduction in circulating cholesterol-containing lipoproteins.


Author(s):  
Silvana Duran-Ortiz ◽  
Kathryn L. Corbin ◽  
Ishrat Jahan ◽  
Nicholas B. Whitticar ◽  
Sarah E Morris ◽  
...  

In the endocrine pancreas, growth hormone (GH) is known to promote pancreatic islet growth and insulin secretion. In this study, we show that GH receptor (GHR) loss in the germline and in adulthood impacts islet mass in general but more profoundly in male mice. GHR knockout (GHRKO) mice have enhanced insulin sensitivity and low circulating insulin. We show that the total cross-sectional area of isolated islets (estimated islet mass) was reduced by 72% in male but by only 29% in female GHRKO mice compared to wild type controls. Also, islets from GHRKO mice secreted ~50% less glucose-stimulated insulin compared to size-matched islets from wild type mice. We next used mice with a floxed Ghr gene to knock down the GHR in adult mice at six-months of age (6mGHRKO) and examined the impact on glucose and islet metabolism. By 12-months of age, female 6mGHRKO mice had increased body fat and reduced islet mass but had no change in glucose tolerance or insulin sensitivity. However, male 6mGHRKO mice had nearly twice as much body fat, substantially reduced islet mass, and enhanced insulin sensitivity, but no change in glucose tolerance. Despite large losses in islet mass, glucose-stimulated insulin secretion from isolated islets was not significantly different between male 6mGHRKO and controls while isolated islets from female 6mGHRKO mice showed increased glucose-stimulated insulin release. Our findings demonstrate the importance of GH to islet mass throughout life and that unique sex-specific adaptations to the loss of GH signaling allow mice to maintain normal glucose metabolism.


Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 311 ◽  
Author(s):  
Sunmin Park ◽  
Ting Zhang ◽  
Jing Yi Qiu ◽  
Xuangao Wu ◽  
Jeong-Yong Lee ◽  
...  

Silk fibroin hydrolysates have been reported to reduce hyperglycemia, but the mechanism has not been determined in Asian type 2 diabetes (T2DM). We hypothesized that the consumption of acid hydrolyzed silk peptides (SPs) alleviates hyperglycemia by improving insulin sensitivity and subsequently normalizing glucose-stimulated insulin secretion in T2DM. We investigated this hypothesis in a partial pancreatectomized (Px) rat model. Px rats was assigned randomly to the following six groups and fed assigned diet for 8 weeks: the Px-control (0.5 g/kg/day dextrin), the SP-L (0.05 g/kg/day), the SP-M (0.1 g/kg/day), the SP-H (0.5 g/kg/day), the positive-control (40 mg/kg/day metformin), or the normal-control (sham-operated rats; 0.5 g/kg/day dextrin). SPs contained high levels of glycine, alanine, and serine. We found SPs dose-dependently increased food efficiency and body weight gain in Px rats. Animals in the Px-control group rats exhibited lower glucose metabolism, as evidenced by impaired glucose-stimulated insulin secretion coupled with impaired insulin sensitivity, and reduced bone mineral density (BMD) and lean body mass (LBM), compared to the normal-control. SPs and metformin similarly partially protected against Px-induced BMD loss in the lumbar spine and femur. Px-induced decreases in LBM were dose-dependently prevented by SPs, and muscle forces in the SP-M and SP-H groups were maintained at the normal-control level. Glucose tolerance was dose-dependently improved by SPs as determined by oral glucose tolerance and oral maltose tolerance tests, and glucose tolerances were similar in the SP-H and positive-control groups. Insulin tolerance, an index of insulin sensitivity, was dose-dependently enhanced by SPs, and the SP-H group exhibited better insulin tolerance than the positive-control group as determined by intraperitoneal insulin sensitivity testing. Insulin secretory capacity assessed using a hyperglycemic clamp improved in the following order: Px-control <SA-L <SA-M <positive-control <SA-H <normal-control. SP-M prevented gut microbiota dysbiosis. In conclusion, SPs administered at 0.1–0.5 g/kg/day improved glucose regulation by potentiating both insulin secretion and insulin sensitivity in non-obese T2DM rats.


Nutrients ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 2207 ◽  
Author(s):  
Mitchell ◽  
Milan ◽  
Mitchell ◽  
Gillies ◽  
D’Souza ◽  
...  

Higher dietary protein intake is increasingly recommended for the elderly; however, high protein diets have also been linked to increased cardiovascular disease (CVD) risk. Trimethylamine-N-oxide (TMAO) is a bacterial metabolite derived from choline and carnitine abundant from animal protein-rich foods. TMAO may be a novel biomarker for heightened CVD risk. The purpose of this study was to assess the impact of a high protein diet on TMAO. Healthy men (74.2 ± 3.6 years, n = 29) were randomised to consume the recommended dietary allowance of protein (RDA: 0.8 g protein/kg bodyweight/day) or twice the RDA (2RDA) as part of a supplied diet for 10 weeks. Fasting blood samples were collected pre- and post-intervention for measurement of TMAO, blood lipids, glucose tolerance, insulin sensitivity, and inflammatory biomarkers. An oral glucose tolerance test was also performed. In comparison with RDA, the 2RDA diet increased circulatory TMAO (p = 0.002) but unexpectedly decreased renal excretion of TMAO (p = 0.003). LDL cholesterol was increased in 2RDA compared to RDA (p = 0.049), but no differences in other biomarkers of CVD risk and insulin sensitivity were evident between groups. In conclusion, circulatory TMAO is responsive to changes in dietary protein intake in older healthy males.


2020 ◽  
Vol 8 (1) ◽  
pp. e001062
Author(s):  
Priyathama Vellanki ◽  
Darko Stefanovski ◽  
Isabel I Anzola ◽  
Dawn D Smiley ◽  
Limin Peng ◽  
...  

IntroductionMany African-Americans (AA) with obesity with newly diagnosed diabetes presenting with diabetic ketoacidosis (DKA) or severe hyperglycemia (SH) discontinue insulin therapy and achieve near-normoglycemia remission (hemoglobin A1c (HbA1c) <7%, fasting blood glucose (FBG) <130 mg/dL) and able to be managed on oral antidiabetic agents (OAD) during follow-up. Using combined data from two randomized controlled trials, we assessed long-term carbohydrate tolerance and changes in insulin sensitivity and insulin secretion.Research design and methodsSeventy-five participants with DKA (n=33) and SH (n=42) underwent 2-hour 75 g oral glucose tolerance test (OGTT) after insulin discontinuation and every 6 months until hyperglycemia relapse (FBG ≥130 mg/dL, HbA1c >7% or two random BG ≥180 mg/dL) while treated with OAD (metformin, sitagliptin or pioglitazone) or placebo. Glucose tolerance status was defined as per the American Diabetes Association. Sensitivity index (Si) was calculated by oral minimal model, insulin secretion as the incremental area under the curve of insulin (IncreAUCi) and disposition index (DI) as Si×IncreAUCi.ResultsDuring remission, OGTT showed normal glucose tolerance (NGT) (n=9 (12%)), prediabetes (n=34 (45%)) and diabetes (n=32 (43%)). DI and Si were higher in patients with NGT versus prediabetes versus diabetes (p<0.001), while IncreAUCi was not significantly different among NGT, prediabetes and diabetes (p=0.14). Achieving NGT status did not prolong near-normoglycemia remission. OAD treatment significantly prolonged hyperglycemia relapse-free survival (log-rank p=0.0012) compared with placebo and was associated with lower hyperglycemia relapse (HR: 0.45, 95% CI: (0.21 to 0.96), p=0.04).ConclusionsIn AA patients with obesity with history of DKA and SH, near-normoglycemia remission is associated with improved insulin secretion and action with half of patients achieving NGT or prediabetes, and only half having diabetes on OGTT. NGT and prediabetes on OGTT were not associated with prolonged hyperglycemia relapse-free survival.Trial registration numberNCT01099618, NCT00426413.


Author(s):  
Malgorzata Malczewska-Malec ◽  
Iwona Wybranska ◽  
Iwona Leszczynska-Golabek ◽  
Lukasz Partyka ◽  
Jadwiga Hartwich ◽  
...  

AbstractThis study analyzes the relationship between risk factors related to overweight/obesity, insulin resistance, lipid tolerance, hypertension, endothelial function and genetic polymorphisms associated with: i) appetite regulation (leptin, melanocortin-3-receptor (MCR-3), dopamine receptor 2 (D2R)); ii) adipocyte differentiation and insulin sensitivity (peroxisome proliferator-activated receptor-γThe 122 members of 40 obese Caucasian families from southern Poland participated in the study. The genotypes were analyzed by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) or by direct sequencing. Phenotypes related to obesity (body mass index (BMI), fat/lean body mass composition, waist-to-hip ratio (WHR)), fasting lipids, glucose, leptin and insulin, as well as insulin during oral glucose tolerance test (OGTT) (4 points within 2 hours) and during oral lipid tolerance test (OLTT) (5 points within 8 hours) were assessed. The insulin sensitivity indexes: homeostasis model assessment of insulin resistance, whole body insulin sensitivity index, hepatic insulin sensitivity and early secretory response to an oral glucose load (HOMA-IR, ISI-COMP, ISI-HOMA and DELTA) were calculated.The single gene mutations such as CWe conclude that the polymorphisms we investigated were weakly correlated with obesity but significantly modified the risk factors of the metabolic syndrome.


2004 ◽  
Vol 89 (3) ◽  
pp. 1096-1101 ◽  
Author(s):  
Catherine W. Yeckel ◽  
Ram Weiss ◽  
James Dziura ◽  
Sara E. Taksali ◽  
Sylvie Dufour ◽  
...  

Abstract Given the extreme increase in prediabetes, type 2 diabetes, and the potential for metabolic syndrome in obese youth, identifying simplified indexes for assessing stimulated insulin sensitivity is critical. The purpose of this study was validation of two surrogate indexes of insulin sensitivity determined from the oral glucose tolerance test (OGTT): the composite whole body insulin sensitivity index (WBISI) and the insulin sensitivity index (ISI). An obese population (aged 8–18 yr) of normal and impaired glucose tolerance individuals was studied. One group (n = 38) performed both the euglycemic-hyperinsulinemic clamp and OGTT for comparison of insulin sensitivity measurements as well as 1H-magnetic resonance spectroscopy estimates of intramyocellular lipid content. Another larger (n = 368) cohort participated only in an OGTT. Both the WBISI and ISI represented good estimates (r = 0.78 and 0.74; P &lt; 0.0005) for clamp-derived insulin sensitivity (glucose disposed, M-value), respectively. In the large cohort, the surrogate indexes demonstrated the shift toward poorer function and increased risk profile as a function of insulin resistance. Additionally, the WBISI and ISI correlated with intramyocellular lipid content (r = −0.74 and −0.71; P &lt; 0.0001), a tissue marker for insulin resistance. Insulin sensitivity can be estimated using plasma glucose and insulin responses derived from the OGTT in obese youth with normal and impaired glucose tolerance.


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