β-Glycosphingolipids improve glucose intolerance and hepatic steatosis of the Cohen diabetic rat

2009 ◽  
Vol 296 (1) ◽  
pp. E72-E78 ◽  
Author(s):  
Ehud Zigmond ◽  
Sarah W. Zangen ◽  
Orit Pappo ◽  
Miriam Sklair-Levy ◽  
Gadi Lalazar ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Immune System ◽  
Glucose Tolerance ◽  
Immune Modulation ◽  
Cell Function ◽  
Liver Steatosis ◽  
Diabetic Rat ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Mri Imaging

A link between altered levels of various gangliosides and the development of insulin resistance was described in transgenic mice. Naturally occurring glycosphingolipids were shown to exert immunomodulatory effects in a natural killer T (NKT) cell-dependent manner. This study examined whether glycosphingolipid-induced modulation of the immune system may reduce pancreatic and liver steatosis and stimulate insulin secretion in the Cohen diabetes-sensitive (CDS) rat, a lean model of non-insulin-resistant, nutritionally induced diabetes. Four groups of CDS rats fed a diabetogenic diet were treated with daily intraperitoneal injections of glycosphingolipids β-glucosylceramide, β-lactosylceramide, a combination of both (IGL), or vehicle (PBS) for up to 45 days. Immune modulation was assessed by fluorescence-activated cell sorting analysis of intrahepatic and intrasplenic lymphocytes. Steatosis was assessed by MRI imaging and histological examination of liver and pancreas, Blood glucose and plasma insulin concentrations were assessed during an oral glucose tolerance test. Administration of glycosphingolipids, particularly IGL, increased intrahepatic trapping of CD8 T and NKT lymphocytes. Pancreatic and liver histology were markedly improved and steatosis was reduced in all treated groups compared with vehicle-treated rats. Insulin secretion was restored after glycosphingolipid treatment, resulting in improved glucose tolerance. The immunomodulatory effect of β-glycosphingolipids improved the β-cell function of the hyperglycemic CDS rat. Thus our results suggest a role for the immune system in the pathogenesis of diabetes in this model.

scholarly journals Meal feeding improves oral glucose tolerance in male rats and causes adaptations in postprandial islet hormone secretion that are independent of plasma incretins or glycemia

2014 ◽  
Vol 307 (9) ◽  
pp. E784-E792 ◽  
Author(s):  
Torsten P. ◽  
Benedikt A. Aulinger ◽  
Eric P. Smith ◽  
Deborah L. Drazen ◽  
Yve Ulrich-Lai ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Hormone Secretion ◽  
Insulin Response ◽  
Male Rats ◽  
Oral Glucose ◽  
Light Cycle ◽  
Oral Glucose Tolerance ◽  
Islet Hormone

Meal-fed (MF) rats with access to food for only 4 consecutive hours during the light cycle learn to eat large meals to maintain energy balance. MF animals develop behavioral and endocrine changes that permit glucose tolerance despite increased meal size. We hypothesized that enhanced activity of the enteroinsular axis mediates glucose homeostasis during MF. Cohorts of rats were allocated to MF or ad libitum (AL) regimens for 2–4 wk. Insulin secretion and glucose tolerance were determined after oral carbohydrate and intraperitoneal (ip) and intravenous (iv) glucose. MF rats ate less than AL in the first week but maintained a comparable weight trajectory thereafter. MF rats had decreased glucose excursions after a liquid mixed meal (AUC: MF 75 ± 7, AL 461 ± 28 mmol·l−1·min, P < 0.001), with left-shifted insulin secretion (AUC0–15: MF 31.0 ± 4.9, AL 9.6 ± 4.4 pM·min, P < 0.02), which peaked before a significant rise in blood glucose. Both groups had comparable fasting glucagon levels, but postprandial responses were lower with MF. However, neither intestinal expression of proGIP and proglucagon mRNA nor plasma incretin levels differed between MF and AL groups. There were no differences in the insulin response to ip or iv glucose between MF and AL rats. These findings demonstrate that MF improves oral glucose tolerance and is associated with significant changes in postprandial islet hormone secretion. Because MF enhanced β-cell function during oral but not parenteral carbohydrate administration, and was not accounted for by changes in circulating incretins, these results support a neural mechanism of adaptive insulin secretion.

Sitagliptin prevents the development of metabolic and hormonal disturbances, increased β-cell apoptosis and liver steatosis induced by a fructose-rich diet in normal rats

2010 ◽  
Vol 120 (2) ◽  
pp. 73-80 ◽  
Author(s):  
Bárbara Maiztegui ◽  
María I. Borelli ◽  
Viviana G. Madrid ◽  
Héctor Del Zotto ◽  
María A. Raschia ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Cell Function ◽  
Liver Steatosis ◽  
Cell Mass ◽  
Oral Glucose ◽  
Model Assessment ◽  
Metabolic Disturbances ◽  
Β Cell ◽  
Commercial Diet ◽  
Triacylglycerol Content

The aim of the present study was to test the effect of sitagliptin and exendin-4 upon metabolic alterations, β-cell mass decrease and hepatic steatosis induced by F (fructose) in rats. Normal adult male Wistar rats received a standard commercial diet without (C) or with 10% (w/v) F in the drinking water (F) for 3 weeks; animals from each group were randomly divided into three subgroups: untreated (C and F) and simultaneously receiving either sitagliptin (CS and FS; 115.2 mg/day per rat) or exendin-4 (CE and FE; 0.35 nmol/kg of body weight, intraperitoneally). Water and food intake, oral glucose tolerance, plasma glucose, triacylglycerol (triglyceride), insulin and fructosamine concentration, HOMA-IR [HOMA (homoeostasis model assessment) for insulin resistance], HOMA-β (HOMA for β-cell function) and liver triacylglycerol content were measured. Pancreas immunomorphometric analyses were also performed. IGT (impaired glucose tolerance), plasma triacylglycerol, fructosamine and insulin levels, HOMA-IR and HOMA-β indexes, and liver triacylglycerol content were significantly higher in F rats. Islet β-cell mass was significantly lower in these rats, due to an increase in the percentage of apoptosis. The administration of exendin-4 and sitagliptin to F animals prevented the development of all the metabolic disturbances and the changes in β-cell mass and fatty liver. Thus these compounds, useful in treating Type 2 diabetes, would also prevent/delay the progression of early metabolic and tissue markers of this disease.

Impact of incretin hormones on β-cell function in subjects with normal or impaired glucose tolerance

2006 ◽  
Vol 291 (6) ◽  
pp. E1144-E1150 ◽  
Author(s):  
Elza Muscelli ◽  
Andrea Mari ◽  
Andrea Natali ◽  
Brenno D. Astiarraga ◽  
Stefania Camastra ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Tolerance ◽  
Impaired Glucose Tolerance ◽  
Cell Function ◽  
Oral Glucose ◽  
Incretin Effect ◽  
Β Cell ◽  
Β Cell Function ◽  
Glucose Sensitivity ◽  
Cell Glucose

The mechanisms by which the enteroinsular axis influences β-cell function have not been investigated in detail. We performed oral and isoglycemic intravenous (IV) glucose administration in subjects with normal (NGT; n = 11) or impaired glucose tolerance (IGT; n = 10), using C-peptide deconvolution to calculate insulin secretion rates and mathematical modeling to quantitate β-cell function. The incretin effect was taken to be the ratio of oral to IV responses. In NGT, incretin-mediated insulin release [oral glucose tolerance test (OGTT)/IV ratio = 1.59 ± 0.18, P = 0.004] amounted to 18 ± 2 nmol/m2 (32 ± 4% of oral response), and its time course matched that of total insulin secretion. The β-cell glucose sensitivity (OGTT/IV ratio = 1.52 ± 0.26, P = 0.02), rate sensitivity (response to glucose rate of change, OGTT/IV ratio = 2.22 ± 0.37, P = 0.06), and glucose-independent potentiation were markedly higher with oral than IV glucose. In IGT, β-cell glucose sensitivity (75 ± 14 vs. 156 ± 28 pmol·min−1·m−2·mM−1 of NGT, P = 0.01) and potentiation were impaired on the OGTT. The incretin effect was not significantly different from NGT in terms of plasma glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide responses, total insulin secretion, and enhancement of β-cell glucose sensitivity (OGTT/IV ratio = 1.73 ± 0.24, P = NS vs. NGT). However, the time courses of incretin-mediated insulin secretion and potentiation were altered, with a predominance of glucose-induced vs. incretin-mediated stimulation. We conclude that, under physiological circumstances, incretin-mediated stimulation of insulin secretion results from an enhancement of all dynamic aspects of β-cell function, particularly β-cell glucose sensitivity. In IGT, β-cell function is inherently impaired, whereas the incretin effect is only partially affected.

scholarly journals Glucose metabolic disorder in Klinefelter syndrome: a retrospective analysis in a single Chinese hospital and literature review

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shixuan Liu ◽  
Tao Yuan ◽  
Shuoning Song ◽  
Shi Chen ◽  
Linjie Wang ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Literature Review ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Klinefelter Syndrome ◽  
Oral Glucose ◽  
Model Assessment ◽  
Β Cell ◽  
Β Cell Function

Abstract Background We aimed to investigate the clinical characteristics and islet β-cell function in patients with Klinefelter syndrome (KS) and hyperglycemia. Methods This is a retrospective study. In total, 22 patients diagnosed with KS were identified from the electronic medical record system, including 9 patients with hyperglycemia (total patients with hyperglycemia, THG-KS group) and 5 hyperglycemic KS patients with oral glucose tolerance test (OGTT) results (HG-KS group). An additional 5 subjects with hyperglycemia and 5 normal glucose tolerance (NGT) subjects matched based on body mass index were included as the HG group and NGT group, respectively. Data from clinical and laboratory examinations were collected. We further performed a literature review of KS and hyperglycemia. Results We found that KS patients developed abnormal glucose metabolism earlier in life than those without KS, and the median age was 17 years, ranging from 10 years to 19 years. Six of 17 (35.3%) patients were diagnosed with diabetes mellitus and 3 of 17 (17.6%) patients were diagnosed with prediabetes. Among 10 patients with both fasting blood glucose and insulin results recorded, there were 8 out of 17 (47.1%) KS patients had insulin resistance. The prevalence of hypertension and dyslipidemia was higher in patients with hyperglycemia and KS than in patients with NGT KS. Compared with the HG group, insulin sensitivity levels were lower in HG-KS group, whereas homeostasis model assessment of β-cell function levels (p = 0.047) were significantly, indicating higher insulin secretion levels in the HG-KS group. Conclusions KS patients develop hyperglycemia earlier in life than those without KS and show lower insulin sensitivity and higher insulin secretion. These patients also have a higher prevalence of other metabolic diseases and may have different frequencies of developing KS-related symptoms.

scholarly journals Interplay of Dinner Timing and MTNR1B Type 2 Diabetes Risk Variant on Glucose Tolerance and Insulin Secretion: A Randomized Crossover Trial

Diabetes Care ◽  
2022 ◽  
Author(s):  
Marta Garaulet ◽  
Jesus Lopez-Minguez ◽  
Hassan S. Dashti ◽  
Céline Vetter ◽  
Antonio Miguel Hernández-Martínez ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Insulin Response ◽  
Area Under The Curve ◽  
Oral Glucose ◽  
Elevated Concentration ◽  
Endogenous Melatonin

OBJECTIVE We tested whether the concurrence of food intake and elevated concentration of endogenous melatonin, as occurs in late eating, results in impaired glucose control, in particular in carriers of the type 2 diabetes–associated G allele in the melatonin receptor-1b gene (MTNR1B). RESEARCH DESIGN AND METHODS In a Spanish natural late-eating population, a randomized, crossover study was performed. Each participant (n = 845) underwent two evening 2-h 75-g oral glucose tolerance tests following an 8-h fast: an early condition scheduled 4 h prior to habitual bedtime (“early dinner timing”) and a late condition scheduled 1 h prior to habitual bedtime (“late dinner timing”), simulating an early and a late dinner timing, respectively. Differences in postprandial glucose and insulin responsesbetween early and late dinner timing were determined using incremental area under the curve (AUC) calculated by the trapezoidal method. RESULTS Melatonin serum levels were 3.5-fold higher in the late versus early condition, with late dinner timing resulting in 6.7% lower insulin AUC and 8.3% higher glucose AUC. In the late condition, MTNR1B G-allele carriers had lower glucose tolerance than noncarriers. Genotype differences in glucose tolerance were attributed to reductions in β-cell function (P for interaction, Pint glucose area under the curve = 0.009, Pint corrected insulin response = 0.022, and Pint Disposition Index = 0.018). CONCLUSIONS Concurrently high endogenous melatonin and carbohydrate intake, as typical for late eating, impairs glucose tolerance, especially in MTNR1B G-risk allele carriers, attributable to insulin secretion defects.

scholarly journals Identification of insulin secretory defects and insulin resistance during oral glucose tolerance test in a cohort of cystic fibrosis patients

2011 ◽  
Vol 165 (1) ◽  
pp. 69-76 ◽  
Author(s):  
A Battezzati ◽  
A Mari ◽  
L Zazzeron ◽  
G Alicandro ◽  
L Claut ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Glucose Tolerance Test ◽  
Cell Function ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Β Cell ◽  
Β Cell Function

BackgroundCystic fibrosis (CF)-related diabetes is a leading complication of CF and is associated with pulmonary and nutritional deterioration, years before an evident hyperglycemia, possibly because of insulin deficiency and resistance.AimTo evaluate glucose tolerance, insulin secretion, and insulin sensitivity by a widely applicable method suitable for accurate and prospective measurements in a CF population.MethodsA total of 165 CF subjects (80 females) aged 17±5 years and 18 age- and sex-matched healthy controls (CON) received an oral glucose tolerance test with glucose, insulin and C-peptide determinations. Insulin sensitivity was defined on the basis of glucose and insulin concentrations using the oral glucose insulin sensitivity index, whereas β-cell function was determined on the basis of a model relating insulin secretion (C-peptide profile) to glucose concentration.ResultsFifteen percent of CF patients had glucose intolerance and 6% had diabetes without fasting hyperglycemia and 3% had diabetes with fasting hyperglycemia. β-cell function was reduced in CF patients compared with CON (70.0±4.1 vs 117.9±11.6 pmol/min per m2 per mM, P<0.001) and decreased significantly with age by −2.7 pmol/min per m2 per mM per year (confidence interval (CI) −4.5 to −0.82), i.e. almost 4% yearly. The early insulin secretion index was also reduced. Insulin sensitivity was similar to CON. CF patients who attained glucose tolerance comparable to CON had lower β-cell function and higher insulin sensitivity.ConclusionThe major alteration in insulin secretion and insulin sensitivity of CF patients is slowly declining β-cell function, consisting of delayed and reduced responsiveness to hyperglycemia, that in CF patients with normal glucose tolerance may be compensated by an increased insulin sensitivity.

Exposure to Glucocorticoids in the First Part of Fetal Life is Associated with Insulin Secretory Defect in Adult Humans

2019 ◽  
Vol 105 (3) ◽  
pp. e191-e199 ◽  
Author(s):  
Jean-Pierre Riveline ◽  
Baz Baz ◽  
Jean-Louis Nguewa ◽  
Tiphaine Vidal-Trecan ◽  
Fidaa Ibrahim ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Glucagon Secretion ◽  
Oral Glucose ◽  
Fetal Life ◽  
Insulinogenic Index ◽  
Hydroxylase Deficiency ◽  
21 Hydroxylase Deficiency

Abstract Objective High glucocorticoid levels in rodents inhibit development of beta cells during fetal life and lead to insulin deficiency in adulthood. To test whether similar phenomena occur in humans, we compared beta-cell function in adults who were exposed to glucocorticoids during the first part of fetal life with that of nonexposed subjects. Research Design and Methods The study was conducted in 16 adult participants exposed to glucocorticoids during the first part of fetal life and in 16 nonexposed healthy participants with normal glucose tolerance who were matched for age, sex, and body mass index (BMI). Exposed participants had been born to mothers who were treated with dexamethasone 1 to 1.5 mg/day from the sixth gestational week (GW) to prevent genital virilization in children at risk of 21-hydroxylase deficiency. We selected offspring of mothers who stopped dexamethasone before the 18th GW following negative genotyping of the fetus. Insulin and glucagon secretion were measured during an oral glucose tolerance test (OGTT) and graded intravenous (IV) glucose and arginine tests. Insulin sensitivity was measured by hyperinsulinemic-euglycemic-clamp. Results Age, BMI, and anthropometric characteristics were similar in the 2 groups. Insulinogenic index during OGTT and insulin sensitivity during the clamp were similar in the 2 groups. In exposed subjects, insulin secretion during graded IV glucose infusion and after arginine administration decreased by 17% (P = 0.02) and 22% (P = 0.002), respectively, while glucagon secretion after arginine increased. Conclusion Overexposure to glucocorticoids during the first part of fetal life is associated with lower insulin secretion at adult age, which may lead to abnormal glucose tolerance later in life.

scholarly journals 4-Hydroxyisoleucine: experimental evidence of its insulinotropic and antidiabetic properties

1999 ◽  
Vol 277 (4) ◽  
pp. E617-E623 ◽  
Author(s):  
Christophe Broca ◽  
René Gross ◽  
Pierre Petit ◽  
Yves Sauvaire ◽  
Michèle Manteghetti ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Insulin Response ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Insulin Dependent ◽  
Glucose Tolerance Tests ◽  
Insulin Dependent Diabetic ◽  
Single Intravenous Administration

We have recently shown in vitro that 4-hydroxyisoleucine (4-OH-Ile), an amino acid extracted from fenugreek seeds, potentiates insulin secretion in a glucose-dependent manner. The present study was designed to investigate whether 4-OH-Ile could exert in vivo insulinotropic and antidiabetic properties. For this purpose, intravenous or oral glucose tolerance tests (IVGTTs and OGTTs, respectively) were performed not only in normal animals but also in a type II diabetes rat model. During IVGTT in normal rats or OGTT in normal dogs, 4-OH-Ile (18 mg/kg) improved glucose tolerance. The lactonic form of 4-OH-Ile was ineffective in normal rats. In non-insulin-dependent diabetic (NIDD) rats, a single intravenous administration of 4-OH-Ile (50 mg/kg) partially restored glucose-induced insulin response without affecting glucose tolerance; a 6-day subchronic administration of 4-OH-Ile (50 mg/kg, daily) reduced basal hyperglycemia, decreased basal insulinemia, and slightly, but significantly, improved glucose tolerance. In vitro, 4-OH-Ile (200 μM) potentiated glucose (16.7 mM)-induced insulin release from NIDD rat-isolated islets. So, the antidiabetic effects of 4-OH-Ile on NIDD rats result, at least in part, from a direct pancreatic B cell stimulation.

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