Dietary fish oil normalized glucose-stimulated insulin secretion in isolated pancreatic islets of dyslipemic rats through mechanisms involving glucose phosphorylation, peroxisome proliferator-activated receptor γ and uncoupling protein 2

2013 ◽  
Vol 89 (1) ◽  
pp. 31-38 ◽  
Author(s):  
M.R. Ferreira ◽  
A. Chicco ◽  
Y.B. Lombardo
2018 ◽  
Vol 9 (4) ◽  
pp. 2496-2507
Author(s):  
Dante Selenscig ◽  
María del Rosario Ferreira ◽  
Adriana Chicco ◽  
Yolanda B. Lombardo

Dietary fish oil exerts beneficial effects on the adipose tissue dysfunction in dyslipemic insulin-resistant rats fed a sucrose-rich diet.


Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3266-3276 ◽  
Author(s):  
Kim Ravnskjaer ◽  
Michael Boergesen ◽  
Blanca Rubi ◽  
Jan K. Larsen ◽  
Tina Nielsen ◽  
...  

Abstract Fatty acids (FAs) are known to be important regulators of insulin secretion from pancreatic β-cells. FA-coenzyme A esters have been shown to directly stimulate the secretion process, whereas long-term exposure of β-cells to FAs compromises glucose-stimulated insulin secretion (GSIS) by mechanisms unknown to date. It has been speculated that some of these long-term effects are mediated by members of the peroxisome proliferator-activated receptor (PPAR) family via an induction of uncoupling protein-2 (UCP2). In this study we show that adenoviral coexpression of PPARα and retinoid X receptor α (RXRα) in INS-1E β-cells synergistically and in a dose- and ligand-dependent manner increases the expression of known PPARα target genes and enhances FA uptake and β-oxidation. In contrast, ectopic expression of PPARγ/RXRα increases FA uptake and deposition as triacylglycerides. Although the expression of PPARα/RXRα leads to the induction of UCP2 mRNA and protein, this is not accompanied by reduced hyperpolarization of the mitochondrial membrane, indicating that under these conditions, increased UCP2 expression is insufficient for dissipation of the mitochondrial proton gradient. Importantly, whereas expression of PPARγ/RXRα attenuates GSIS, the expression of PPARα/RXRα potentiates GSIS in rat islets and INS-1E cells without affecting the mitochondrial membrane potential. These results show a strong subtype specificity of the two PPAR subtypes α and γ on lipid partitioning and insulin secretion when systematically compared in a β-cell context.


2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Meicen Zhou ◽  
Shuli He ◽  
Fan Ping ◽  
Wei Li ◽  
Lixin Zhu ◽  
...  

Objective. To investigate the association of polymorphisms in uncoupling protein 2 (UCP2) and peroxisome proliferator-activated receptor (PPARγ) with glucolipid metabolism in Chinese Han population. Methods. Five hundred eighty-nine subjects were divided into normal glucose tolerance (NGT) group (n=198) and abnormal glucose tolerance group (n=358). HbA1c, blood lipid profile, plasma glucose, and insulin were determined. Insulin sensitivity (HOMA-IR and Matsuda index (ISIM)) and insulin secretion indexes (HOMA-β, early and total phase disposition index) were evaluated. Eight potential functional SNPs in UCP2 and 7 in PPARγ were selected. SNPs were genotyped on Sequenom MassARRAY platform. Results. The GG genotype of rs2920502 in PPARγ was associated with decreased risk of impaired glucose tolerance (G allele: OR: 0.818, 95%CI: 0.526–0.969, P=0.042; GG: OR: 0.715, 95%CI: 0.527–0.97, P=0.031). The TT genotype of rs3856806 in PPARγ was associated with increased risk of impaired glucose tolerance (T allele: OR: 1.46, 95%CI: 1.055–2.017, P=0.022; TT: OR: 1.58, 95%CI: 1.104–2.761, P=0.032). The GG genotype of rs2920502 in PPARγ had better blood glucose and increased insulin secretion and had lower HOMA-IR than GC/CC genotypes. Conclusion. It probably could prevent insulin resistance in early stage by classifying the genotype of rs649446 and rs7109266 in UCP2. The GG genotype of rs2920502 in PPARγ had a decreased risk for diabetes. The TT genotype of rs3856806 in PPARγ had an increased risk for diabetes.


2012 ◽  
Vol 287 (47) ◽  
pp. 39673-39685 ◽  
Author(s):  
Ryan J. Mailloux ◽  
Accalia Fu ◽  
Christine Robson-Doucette ◽  
Emma M. Allister ◽  
Michael B. Wheeler ◽  
...  

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 375-382 ◽  
Author(s):  
Sandrine Gremlich ◽  
Christopher Nolan ◽  
Raphaël Roduit ◽  
Rémy Burcelin ◽  
Marie-Line Peyot ◽  
...  

The cellular response to fasting and starvation in tissues such as heart, skeletal muscle, and liver requires peroxisome proliferator-activated receptor-α (PPARα)-dependent up-regulation of energy metabolism toward fatty acid oxidation (FAO). PPARα null (PPARαKO) mice develop hyperinsulinemic hypoglycemia in the fasting state, and we previously showed that PPARα expression is increased in islets at low glucose. On this basis, we hypothesized that enhanced PPARα expression and FAO, via depletion of lipid-signaling molecule(s) for insulin exocytosis, are also involved in the normal adaptive response of the islet to fasting. Fasted PPARαKO mice compared with wild-type mice had supranormal ip glucose tolerance due to increased plasma insulin levels. Isolated islets from the PPARα null mice had a 44% reduction in FAO, normal glucose use and oxidation, and enhanced glucose-induced insulin secretion. In normal rats, fasting for 24 h increased islet PPARα, carnitine palmitoyltransferase 1, and uncoupling protein-2 mRNA expression by 60%, 62%, and 82%, respectively. The data are consistent with the view that PPARα, via transcriptionally up-regulating islet FAO, can reduce insulin secretion, and that this mechanism is involved in the normal physiological response of the pancreatic islet to fasting such that hypoglycemia is avoided.


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