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Title

Procyanidins modify insulinemia by affecting insulin production and degradation

Authors
Castell-Auví, Anna
Cedó, Lídia
Pallarès, Victor
Blay, M Teresa
Pinent, Montserrat
Motilva, M José
Garcia-Vallvé, Santiago
Pujadas, Gerard
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Published in Journal of Nutritional Biochemistry. 2012, vol. 23, no. 12, p. 1565-72
Abstract Previous studies from our research group have suggested that procyanidins modify glycemia and insulinemia. The aim of this work was to evaluate the effects of procyanidins on β-cell functionality in a nonpathological system. Four groups of healthy rats were studied. The animals were given daily acute doses of grape seed procyanidin extract (GSPE) for different time periods and at different daily amounts. A β-cell line (INS-1E) was treated with 25 mg GSPE/L for 24 h to identify possible mechanisms of action for the procyanidins. In vivo experiments showed that different doses of GSPE affected insulinemia in different ways by modifying β-cell functionality and/or insulin degradation. The islets isolated from rats that were treated with 25 mg GSPE/kg of body weight for 45 days exhibited a limited response to glucose stimulation. In addition, insulin gene expression, insulin synthesis and expression of genes related to insulin secretion were all down-regulated. In vitro studies revealed that GSPE decreased the ability of β-cells to secrete insulin in response to glucose. GSPE increased glucose uptake in β-cells under high-glucose conditions but impaired glucose-induced mitochondrial hyperpolarization, decreased adenosine triphosphate (ATP) synthesis and altered cellular membrane potentials. GSPE also modified Glut2, glucokinase and Ucp2 gene expression as well as altered the expression of hepatic insulin-degrading enzyme (Ide), thereby altering insulin degradation. At some doses, procyanidins changed β-cell functionality by modifying insulin synthesis, secretion and degradation under nonpathological conditions. Membrane potentials and Ide provide putative targets for procyanidins to induce these effects.
Keywords Adenosine Triphosphate/metabolismAnimalsCell LineDose-Response Relationship, DrugFemaleGene Expression Regulation/drug effectsGlucose/metabolism/pharmacologyGlucose Transporter Type 2/geneticsGrape Seed Extract/pharmacologyHomeodomain Proteins/geneticsInsulin/genetics/metabolism/secretionInsulin-Secreting Cells/drug effects/metabolismInsulysin/geneticsIon Channels/geneticsIslets of Langerhans/drug effects/metabolismMembrane Potentials/drug effectsMitochondria/drug effects/metabolismMitochondrial Proteins/geneticsProanthocyanidins/pharmacologyRatsRats, WistarTrans-Activators/genetics
Identifiers
PMID: 22444499
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Structures
Research group Mitochondries et sécrétion d'insuline (671)
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CASTELL-AUVÍ, Anna et al. Procyanidins modify insulinemia by affecting insulin production and degradation. In: Journal of Nutritional Biochemistry, 2012, vol. 23, n° 12, p. 1565-72. https://archive-ouverte.unige.ch/unige:28013

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Deposited on : 2013-05-28

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