Insulinogenic Index (insulinogenic + index)

Distribution by Scientific Domains

Selected Abstracts

Studies of relationships between the GLUT10 Ala206Thr polymorphism and impaired insulin secretion

C. S. Rose
Abstract Aims This study aimed to investigate if the previously observed association between the GLUT10 Ala206Thr polymorphism and variation in fasting and oral glucose-induced serum insulin concentrations could be replicated in a large-scale population-based cohort of Danish whites. Methods The GLUT10 Ala206Thr polymorphism was genotyped in a case-control study of 880 Type 2 diabetic patients and 4372 glucose-tolerant control subjects. The latter group was also enrolled in an assessment of fasting and post-OGTT circulating levels of plasma glucose and serum insulin in relation to genotype. The variant was genotyped by analysis of PCR-generated primer extension by matrix-assisted laser desorption/ionization time-of-flight analysis. Results The Ala206Thr variant was equally frequent among Type 2 diabetic patients and glucose-tolerant subjects (P = 0.9) and there was no difference in the distribution of genotype groups (P = 1.0). In the 4372 glucose-tolerant subjects there was no statistically significant association between the polymorphism and levels of fasting and post-oral glucose tolerance test plasma glucose and serum insulin along with the insulinogenic index and the homeostasis model of assessment for insulin resistance and insulin secretion. Likewise, in an age-stratified subgroup comprising 1264 subjects, we observed no relationships between the GLUT10 polymorphism and the selected metabolic features. Conclusions The GLUT10 Ala206Thr polymorphism is not associated with Type 2 diabetes in the Danish population. Furthermore, in the present large-scale cohort, the polymorphism does not associate with phenotypes such as fasting and oral glucose-induced levels of plasma glucose and serum insulin. [source]

Beta-cell function and insulin sensitivity contribute to the shape of plasma glucose curve during an oral glucose tolerance test in non-diabetic individuals

M. Kanauchi
Summary To clarify whether beta-cell function and/or insulin resistance contributes to the shape of plasma glucose curve during an oral glucose tolerance test (OGTT), we investigated 583 Japanese subjects with normal glucose tolerance (NGT, n = 306) or impaired glucose tolerance (IGT, n = 277). Each subject was subdivided into three shapes of plasma glucose curve as follows: monophasic pattern (M type), biphasic pattern (B type) and two peaks (T type). Homeostasis model assessment of insulin resistance, quantitative insulin sensitivity check index and insulinogenic index were assessed by plasma glucose and insulin concentrations obtained at fasting or during an OGTT. There was a greater proportion of M type in the IGT group (M = 80.9%, B = 15.5% and T = 3.6%), whereas the prevalence of B and T types was much higher in the NGT group (M = 66.6%, B = 26.5% and T = 6.9%). There were significant differences in the proportions of shape types between the NGT and IGT groups (p = 0.0006). Among the NGT category, insulin sensitivity was significantly higher in the B type than in the M type, and beta-cell function adjusted for insulin resistance was significantly higher in the B and T types than in the M type. Among the IGT category, no significant differences were seen among the three shape types with respect to insulin sensitivity, but the beta-cell function adjusted for insulin resistance was significantly lower in the M type than in the B and T types. In conclusion, both impaired insulin secretion and insulin resistance may contribute to the underlying mechanisms of the shape of plasma glucose curve in Japanese subjects. [source]

Glucose tolerance status in 510 children and adolescents attending an obesity clinic in Central Italy

Claudia Brufani
Brufani C, Ciampalini P, Grossi A, Fiori R, Fintini D, Tozzi A, Cappa M, Barbetti F. Glucose tolerance status in 510 children and adolescents attending an obesity clinic in Central Italy. Childhood obesity is epidemic in developed countries and is accompanied by an increase in the prevalence of type 2 diabetes (T2DM). Aims: Establish prevalence of glucose metabolism alterations in a large sample of overweight/obese children and adolescents from Central Italy. Methods: The study group included 510 overweight/obese subjects (3,18 yr). Oral glucose tolerance test (OGTT) was performed with glucose and insulin determination. Homeostatic model assessment of insulin resistance (HOMA-IR) and insulin sensitivity index (ISI) were derived from fasting and OGTT measurements. Beta-cell function was estimated by insulinogenic index. Fat mass was measured by dual-energy x-ray absorptiometry. Results: Glucose metabolism alterations were detected in 12.4% of patients. Impaired glucose tolerance (IGT) was the most frequent alteration (11.2%), with a higher prevalence in adolescents than in children (14.8 vs. 4.1%, p < 0.001); silent T2DM was identified in two adolescents (0.4%). HOMA-IR and glucose-stimulated insulin levels were higher in patients with IGT than individuals with normal glucose tolerance (HOMA-IR = 4.4 ▒ 2.5 vs. 3.4 ▒ 2.3, p = 0.001). Fat mass percentage and insulinogenic index were not different between the two groups. In multivariate analysis, age, fasting glucose, and insulin resistance influenced independently plasma glucose at 120 min of OGTT. Individuals with combined impaired fasting glucose/IGT (IFG/IGT) and T2DM were older and had reduced plasma insulin values at OGTT when compared to patients with simple IGT. Conclusions: Glucose metabolism alterations are frequently found among children and adolescents with overweight/obesity from Central Italy. Age, fasting glucose, and insulin resistance are main predictors of IGT. We suggest the use of OGTT as a screening tool in obese European adolescents. [source]

Robust improvements in fasting and prandial measures of ,-cell function with vildagliptin in drug-na´ve patients: analysis of pooled vildagliptin monotherapy database

R. E. Pratley
Aim:, To assess the effects of 24-week treatment with vildagliptin on measures of ,-cell function in a broad spectrum of drug-na´ve patients with type 2 diabetes (T2DM). Methods:, Data from all double-blind, multicentre, randomized, placebo- or active-controlled trials conducted in drug-na´ve patients with T2DM were pooled from all patients receiving monotherapy with vildagliptin (100 mg daily: 50 mg twice daily or 100 mg once daily, n = 1855) or placebo (n = 347). Fasting measures of ,-cell function [homeostasis model assessment of ,-cell function (HOMA-B) and proinsulin : insulin ratio] were assessed in the overall pooled monotherapy population. Standard meal tests were performed at baseline and week 24 in a subset of patients, and effects of vildagliptin (100 mg daily, n = 227) on dynamic (meal test,derived) measures of ,-cell function [insulin secretion rate relative to glucose (ISR/G) and insulinogenic indices] were assessed relative to baseline and vs. placebo (n = 29). Results:, In the overall population, vildagliptin significantly increased HOMA-B both relative to baseline [adjusted mean change (AM,) = 10.3 ▒ 1.5] and vs. placebo (between-treatment difference in AM, = 11.5 ▒ 4.5, p = 0.01) and significantly decreased the proinsulin : insulin ratio relative to baseline (AM, = ,0.05 ▒ 0.01) and vs. placebo (between-treatment difference in AM, = ,0.09 ▒ 0.02, p < 0.001). Relative to baseline, vildagliptin monotherapy significantly increased all meal test,derived parameters, and ISR/G (between-treatment difference in AM, = 9.8 ▒ 2.8 pmol/min/m2/mM, p < 0.001) and the insulinogenic index0,peak glucose (between-treatment difference in AM, = 0.24 ▒ 0.05 pmol/mmol, p = 0.045) were significantly increased vs. placebo. Conclusions:, Vildagliptin monotherapy consistently produced robust improvements in both fasting and meal test,derived measures of ,-cell function across a broad spectrum of drug-na´ve patients with T2DM. All Phase III trials described (NCT 00099905, NCT 00099866, NCT 00099918, NCT 00101673, NCT 00101803 and NCT 00120536) are registered with [source]