scholarly journals Long-term metabolic consequences of acute dioxin exposure differ between male and female mice

2019 ◽  
Author(s):  
Myriam P Hoyeck ◽  
Hannah Blair ◽  
Muna Ibrahim ◽  
Shivani Solanki ◽  
Mariam Elsawy ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Beta Cell ◽  
Cell Function ◽  
Cell Area ◽  
Male And Female ◽  
Female Mice ◽  
Insulin Levels ◽  
Beta Cell Area

SUMMARYExposure to environmental pollutants is consistently associated with increased diabetes risk in humans. In male mice, acute dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) exposure supresses insulin secretion. This study investigated the long-term effects of a single TCDD injection (20 µg/kg) on glucose metabolism and beta cell function in male and female mice. TCDD-exposed males displayed modest fasting hypoglycemia for ∼4 weeks post-injection, reduced fasting insulin levels for up to 6 weeks, increased insulin sensitivity, and decreased beta cell area. TCDD-exposed females also had long-term suppressed basal plasma insulin levels, and abnormal insulin secretion for up to 6 weeks. Unlike males, TCDD did not impact insulin sensitivity or beta cell area in females, but did cause transient glucose intolerance 4 weeks post-exposure. Our results show that a single exposure to dioxin can supress basal insulin levels long-term in both sexes, but effects on metabolism are sex-dependent.

Impact of cyclosporine and low-dose steroid therapy on insulin sensitivity and beta-cell function in patients with long-term liver grafts

2001 ◽  
Vol 14 (1) ◽  
pp. 6-11
Author(s):  
T. Konrad ◽  
Bernd Markus ◽  
Carl Allers ◽  
Paolo Vicini ◽  
Gianna Toffolo ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Beta Cell ◽  
Steroid Therapy ◽  
Beta Cell Function ◽  
Low Dose ◽  
Cell Function

scholarly journals The Incretin Effect in Female Mice With Double Deletion of GLP-1 and GIP Receptors

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Bo Ahrén ◽  
Yuichiro Yamada ◽  
Yutaka Seino
Keyword(s):  
Insulin Secretion ◽  
Beta Cell ◽  
Beta Cell Function ◽  
Cell Function ◽  
Insulin Response ◽  
Oral Glucose ◽  
Incretin Effect ◽  
Intravenous Glucose ◽  
C Peptide ◽  
Female Mice

Abstract To establish the contribution of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) for the incretin effect after oral glucose, studies were undertaken in female mice with genetic deletion of receptors for GIP and GLP-1 (double incretin receptor knockout [DIRKO] mice) and their wild-type (WT) counterparts. Insulin secretion was explored after oral glucose (doses ranging from 0 to 100 mg), after intravenous glucose (doses ranging from 0 to 0.75 g/kg), and after oral and intravenous glucose at matching circulating glucose. DIRKO mice had glucose intolerance after oral glucose challenges in association with impaired beta-cell function. Suprabasal area under the curve for C-peptide (AUCC-peptide) correlated linearly with suprabasal AUCglucose both in WT (r = 0.942, P = .017) and DIRKO mice (r = 0.972, P = .006). The slope of this regression was lower in DIRKO than in WT mice (0.012 ± 0.006 vs 0.031 ± 0.006 nmol C-peptide/mmol glucose, P = .042). In contrast, there was no difference in the insulin response to intravenous glucose between WT and DIRKO mice. Furthermore, oral and intravenous glucose administration at matching glucose levels showed that the augmentation of insulin secretion after oral glucose (the incretin effect) in WT mice (11.8 ± 2.3 nmol/L min) was entirely absent in DIRKO mice (3.3 ± 1.2 nmol/L min). We conclude that GIP and GLP-1 are required for normal glucose tolerance and beta-cell function after oral glucose in mice, that they are the sole incretin hormones after oral glucose at higher dose levels, and that they contribute by 65% to insulin secretion after oral glucose.

scholarly journals Importance of quantifying insulin secretion in relation to insulin sensitivity to accurately assess beta cell function in clinical studies

2004 ◽  
pp. 97-104 ◽  
Author(s):  
B Ahren ◽  
G Pacini
Keyword(s):  
Insulin Resistance ◽  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Beta Cell ◽  
Beta Cell Function ◽  
Glucose Tolerance Test ◽  
Cell Function ◽  
Tolerance Test ◽  
Hyperbolic Function

Insulin sensitivity and insulin secretion are mutually related such that insulin resistance is compensated by increased insulin secretion. A correct judgement of insulin secretion therefore requires validation in relation to the insulin sensitivity in the same subject. Mathematical analyses of the relationship between insulin sensitivity and insulin secretion has revealed a hyperbolic function, such that the product of the two variables is constant. This product is usually called the disposition index. Several techniques may be used for its estimation such as data derived from the frequently sampled i.v. glucose tolerance test, the oral glucose tolerance test or the glucose-dependent arginine stimulation test or the euglycemic hyperinsulinemic clamp technique in combination with a test on insulin secretion. Using these techniques the compensatory increase in beta cell function in insulin resistance has been verified in obesity, in pregnancy and after glucocorticoid administration as has the defective beta cell function as the underlying cause of impaired glucose tolerance and type 2 diabetes. Similarly, combined analysis of insulin sensitivity and insulin secretion has shown a down-regulation of beta cell function in increased insulin sensitivity accompanying weight reduction in obesity and following exercise. Acknowledging this inverse relationship between insulin secretion and insulin sensitivity therefore requires estimation of both variables for correct assessment in any individual.

scholarly journals Postnatal insulin secretion and sensitivity after manipulation of fetal growth by embryo transfer in the horse

2004 ◽  
Vol 181 (3) ◽  
pp. 459-467 ◽  
Author(s):  
AJ Forhead ◽  
JC Ousey ◽  
WR Allen ◽  
AL Fowden
Keyword(s):  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Beta Cell ◽  
Embryo Transfer ◽  
Plasma Glucose ◽  
Cell Function ◽  
The Other ◽  
Intrauterine Growth ◽  
Cell Responses ◽  
The Relationship

This study examined the effects of intrauterine growth on insulin secretion and resistance in newborn foals. Embryo transfer between small pony and large Thoroughbred mares was used to produce four groups of foals with different birth weights (pony in pony n=7; pony in Thoroughbred n=7; Thoroughbred in Thoroughbred n=8; Thoroughbred in pony n=8). On day 2 after birth, glucose (0.5 g/kg) was administered intravenously to the foal and blood samples were taken for 2 h to determine plasma glucose and insulin concentrations. On day 3, insulin sensitivity was assessed by giving insulin (0.75 U/kg i.v.) and measuring the decrement in plasma glucose in the foals. There were no significant differences in insulin secretion, insulin sensitivity or glucose tolerance between the control and growth-retarded Thoroughbred foals. Overgrown pony foals delivered by Thoroughbred mares had higher basal insulin levels and greater beta cell responses to glucose than the other groups of foals. The relationship between plasma glucose and insulin was also significantly steeper in overgrown pony foals than in the other groups. Variations in intrauterine growth rate, therefore, affect postnatal insulin secretion in the horse. More specifically, it is overgrowth, not growth retardation in utero that alters equine beta cell function in the immediate neonatal period.

scholarly journals Ethnic differences in beta cell function occur independently of insulin sensitivity and pancreatic fat in black and white men

2021 ◽  
Vol 9 (1) ◽  
pp. e002034
Author(s):  
Meera Ladwa ◽  
Oluwatoyosi Bello ◽  
Olah Hakim ◽  
Fariba Shojaee-Moradie ◽  
Maria Linda Boselli ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Beta Cell ◽  
Ethnic Differences ◽  
Beta Cell Function ◽  
Cell Function ◽  
White Men ◽  
Black And White ◽  
Pancreatic Fat ◽  
Postprandial Insulin

IntroductionIt is increasingly recognized that type 2 diabetes (T2D) is a heterogenous disease with ethnic variations. Differences in insulin secretion, insulin resistance and ectopic fat are thought to contribute to these variations. Therefore, we aimed to compare postprandial insulin secretion and the relationships between insulin secretion, insulin sensitivity and pancreatic fat in men of black West African (BA) and white European (WE) ancestry.Research design and methodsA cross-sectional, observational study in which 23 WE and 23 BA men with normal glucose tolerance, matched for body mass index, underwent a mixed meal tolerance test with C peptide modeling to measure beta cell insulin secretion, an MRI to quantify intrapancreatic lipid (IPL), and a hyperinsulinemic-euglycemic clamp to measure whole-body insulin sensitivity.ResultsPostprandial insulin secretion was lower in BA versus WE men following adjustment for insulin sensitivity (estimated marginal means, BA vs WE: 40.5 (95% CI 31.8 to 49.2) × 103 vs 56.4 (95% CI 48.9 to 63.8) × 103 pmol/m2 body surface area × 180 min, p=0.008). There was a significantly different relationship by ethnicity between IPL and insulin secretion, with a stronger relationship in WE than in BA (r=0.59 vs r=0.39, interaction p=0.036); however, IPL was not a predictor of insulin secretion in either ethnic group following adjustment for insulin sensitivity.ConclusionsEthnicity is an independent determinant of beta cell function in black and white men. In response to a meal, healthy BA men exhibit lower insulin secretion compared with their WE counterparts for their given insulin sensitivity. Ethnic differences in beta cell function may contribute to the greater risk of T2D in populations of African ancestry.

scholarly journals Changes induced by sucrose administration on glucose metabolism in pancreatic islets in normal hamsters

2001 ◽  
Vol 171 (3) ◽  
pp. 551-556 ◽  
Author(s):  
ML Massa ◽  
MI Borelli ◽  
H Del Zotto ◽  
JJ Gagliardino
Keyword(s):  
Insulin Secretion ◽  
Blood Glucose ◽  
Glucose Metabolism ◽  
Beta Cell ◽  
Cell Function ◽  
Normal Male ◽  
Insulin Levels ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Glucose Phosphorylation

We correlated the changes in glucose-induced insulin secretion with those observed in glucose metabolism and hexokinase/glucokinase activity in islets from normal sucrose-fed hamsters. Blood glucose and insulin levels were measured in normal male hamsters fed with (S5) or without (C5) 10% sucrose in the drinking water for 5 weeks. Isolated islets (collagenase digestion) from both groups of animals were used to study insulin secretion, (14)CO(2) and (3)H(2)O production from D-[U-(14)C]-glucose and D-[5-(3)H]-glucose respectively, with 3.3 or 16.7 mM glucose in the medium, and hexokinase/glucokinase activity (fluorometric assay) in islet homogenates. Whereas S5 and C5 animals had comparable normal blood glucose levels, S5 showed higher insulin levels than C5 hamsters (2.3+/-0.1 vs 0.6+/-0.03 ng/ml, P<0.001). Islets from S5 hamsters released significantly more insulin than C5 islets in the presence of low and high glucose (3.3 mM glucose: 0.77+/-0.04 vs 0.20+/-0.06 pg/ng DNA/min, P<0.001; 16.7 mM glucose: 2.77+/-0.12 vs 0.85+/-0.06 pg/ng DNA/min, P<0.001) and produced significantly higher amounts of (14)CO(2) and (3)H(2)O at both glucose concentrations ((14)CO(2): 3.3 mM glucose: 0.27+/-0.01 vs 0.18+/-0.01, P<0.001; 16.7 mM glucose: 1.44+/-0.15 vs 0.96+/-0.08, P<0.02; (3)H(2)O: 3.3 mM glucose: 0.31+/-0.02 vs 0.15+/-0.01, P<0.001; 16.7 mM glucose: 1.46+/-0.20 vs 0.76+/-0.05 pmol glucose/ng DNA/min, P<0.005). The hexokinase K(m) and V(max) values from S5 animals were significantly higher than those from C5 ones (K(m): 100.14+/-7.01 vs 59.90+/- 3.95 microM, P<0.001; V(max): 0.010+/-0.0005 vs 0.008+/- 0.0006 pmol glucose/ng DNA/min, P<0.02). Conversely, the glucokinase K(m) value from S5 animals was significantly lower than in C5 animals (K(m): 15.31+/-2.64 vs 35.01+/-1.65 mM, P<0.001), whereas V(max) figures were within a comparable range in both groups (V(max): 0.048+/-0.009 vs 0.094+/-0.035 pmol glucose/ng DNA/min, not significant). The glucose phosphorylation ratio measured at 1 and 100 mM (hexokinase/glucokinase ratio) was significantly higher in S5 (0.26+/-0.02) than in C5 animals (0.11+/-0.01, P<0.005), and it was attributable to an increase in the hexokinase activity in S5 animals. In conclusion, sucrose administration increased the hexokinase/glucokinase activity ratio in the islets, which would condition the increase in glucose metabolism by beta-cells, and in beta-cell sensitivity and responsiveness to glucose. These results support the concept that increased hexokinase rather than glucokinase activity causes the beta-cell hypersensitivity to glucose, hexokinase being metabolically more active than glucokinase to up-regulate beta-cell function.

scholarly journals ZBED6 counteracts high-fat diet-induced glucose intolerance by maintaining beta cell area and reducing excess mitochondrial activation

Diabetologia ◽  
2021 ◽  
Author(s):  
Xuan Wang ◽  
Shady Younis ◽  
Jing Cen ◽  
Yun Wang ◽  
Camilla Krizhanovskii ◽  
...  
Keyword(s):  
Beta Cell ◽  
Glucose Intolerance ◽  
Knockout Mice ◽  
High Fat Diet ◽  
Beta Cell Function ◽  
Cell Function ◽  
Cell Area ◽  
High Fat ◽  
Beta Cell Area

Abstract Aims/hypothesis ZBED6 (zinc finger, BED-type containing 6) is known to regulate muscle mass by suppression of Igf2 gene transcription. In insulin-producing cell lines, ZBED6 maintains proliferative capacity at the expense of differentiation and beta cell function. The aim was to study the impact of Zbed6 knockout on beta cell function and glucose tolerance in C57BL/6 mice. Methods Beta cell area and proliferation were determined in Zbed6 knockout mice using immunohistochemical analysis. Muscle and fat distribution were assessed using micro-computed tomography. Islet gene expression was assessed by RNA sequencing. Effects of a high-fat diet were analysed by glucose tolerance and insulin tolerance tests. ZBED6 was overexpressed in EndoC-βH1 cells and human islet cells using an adenoviral vector. Beta cell cell-cycle analysis, insulin release and mitochondrial function were studied in vitro using propidium iodide staining and flow cytometry, ELISA, the Seahorse technique, and the fluorescent probes JC-1 and MitoSox. Results Islets from Zbed6 knockout mice showed lowered expression of the cell cycle gene Pttg1, decreased beta cell proliferation and decreased beta cell area, which occurred independently from ZBED6 effects on Igf2 gene expression. Zbed6 knockout mice, but not wild-type mice, developed glucose intolerance when given a high-fat diet. The high-fat diet Zbed6 knockout islets displayed upregulated expression of oxidative phosphorylation genes and genes associated with beta cell differentiation. In vitro, ZBED6 overexpression resulted in increased EndoC-βH1 cell proliferation and a reduced glucose-stimulated insulin release in human islets. ZBED6 also reduced mitochondrial JC-1 J-aggregate formation, mitochondrial oxygen consumption rates (OCR) and mitochondrial reactive oxygen species (ROS) production, both at basal and palmitate + high glucose-stimulated conditions. ZBED6-induced inhibition of OCR was not rescued by IGF2 addition. ZBED6 reduced levels of the mitochondrial regulator PPAR-γ related coactivator 1 protein (PRC) and bound its promoter/enhancer region. Knockdown of PRC resulted in a lowered OCR. Conclusions/interpretation It is concluded that ZBED6 is required for normal beta cell replication and also limits excessive beta cell mitochondrial activation in response to an increased functional demand. ZBED6 may act, at least in part, by restricting PRC-mediated mitochondrial activation/ROS production, which may lead to protection against beta cell dysfunction and glucose intolerance in vivo. Graphical abstract

Long-Term Outcomes of Biliopancreatic Diversion on Glycemic Control, Insulin Sensitivity and Beta Cell Function

2016 ◽  
Vol 26 (11) ◽  
pp. 2572-2580 ◽  
Author(s):  
Ana Carolina Junqueira Vasques ◽  
José Carlos Pareja ◽  
Maria da Saúde de Oliveira ◽  
Fernanda Satake Novaes ◽  
Marcelo Miranda Oliveira Lima ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Glycemic Control ◽  
Beta Cell ◽  
Biliopancreatic Diversion ◽  
Beta Cell Function ◽  
Cell Function ◽  
Long Term Outcomes
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