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Title

The Lou/C rat: a model of spontaneous food restriction associated with improved insulin sensitivity and decreased lipid storage in adipose tissue

Authors
Gjinovci, Asllan
Published in American Journal of Physiology. Endocrinology and Metabolism. 2009, vol. 296, no. 5, p. E1120-1132
Abstract The inbred Lou/C rat, originating from the Wistar strain, has been described as a model of resistance to diet-induced obesity, but little is known about its metabolism. Since this knowledge could provide some clues about the etiology of obesity/insulin resistance, this study aimed at characterizing glucose and lipid metabolism in Lou/C vs. Wistar rats. This was achieved by performing glucose and insulin tolerance tests, euglycemic hyperinsulinemic clamps, and characterization of intracellular insulin signaling in skeletal muscle. Substrate-induced insulin secretion was evaluated using perfused pancreas and isolated islets. Finally, body fat composition and the expression of various factors involved in lipid metabolism were determined. Body weight and caloric intake were lower in Lou/C than in Wistar rats, whereas food efficiency was similar. Improved glucose tolerance of Lou/C rats was not related to increased insulin output but was related to improved insulin sensitivity/responsiveness in the liver and in skeletal muscles. In the latter tissue, this was accompanied by improved insulin signaling, as suggested by higher activation of the insulin receptor and of the Akt/protein kinase B pathway. Fat deposition was markedly lower in Lou/C than in Wistar rats, especially in visceral adipose tissue. In the inguinal adipose depot, expression of uncoupling protein-1 was detected in Lou/C but not in Wistar rats, in keeping with a higher expression of peroxisome proliferator-activated receptor-gamma coactivator-1 in these animals. The Lou/C rat is a valuable model of spontaneous food restriction with associated improved insulin sensitivity. Independently from its reduced caloric intake, it also exhibits a preferential channeling of nutrients toward utilization rather than storage.
Keywords Adipose Tissue/*metabolismAnimalsBlood Glucose/metabolismBody Composition/physiologyBody Weight/physiology*Caloric RestrictionDisease Models, AnimalFatty Acids, Nonesterified/blood/metabolismGlucose Tolerance TestInsulin Resistance/*physiologyInsulin-Secreting Cells/metabolismIon Channels/genetics/metabolismMaleMitochondrial Proteins/genetics/metabolismMuscle, Skeletal/metabolismObesity/*metabolismProto-Oncogene Proteins c-akt/genetics/metabolismRNA, Messenger/genetics/metabolismRatsRats, Inbred StrainsReceptor, Insulin/genetics/metabolismReverse Transcriptase Polymerase Chain ReactionSignal Transduction/physiologyTriglycerides/blood/metabolism
Identifiers
PMID: 19208855
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Structures
Research groups Couplage cellulaire et connexines (136)
Imagerie et radiologie interventionnelle du foie, des voies biliaires et du pancréas (316)
Homéostasie métabolique (649)
Obésité et syndrome métabolique (803)
Citation
(ISO format)
VEYRAT-DUREBEX, Christelle et al. The Lou/C rat: a model of spontaneous food restriction associated with improved insulin sensitivity and decreased lipid storage in adipose tissue. In: American Journal of Physiology. Endocrinology and Metabolism, 2009, vol. 296, n° 5, p. E1120-1132. https://archive-ouverte.unige.ch/unige:20153

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Deposited on : 2012-04-23

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