Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/25738
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dc.contributor.authorMartins, Fátima O.-
dc.contributor.authorRito, João-
dc.contributor.authorJarak, Ivana-
dc.contributor.authorViegas, Ivan-
dc.contributor.authorPardal, M. A.-
dc.contributor.authorMacedo, M. Paula-
dc.contributor.authorJones, John G.-
dc.date.accessioned2014-05-14T11:22:31Z-
dc.date.available2014-05-14T11:22:31Z-
dc.date.issued2013-
dc.identifier.urihttp://hdl.handle.net/10316/25738-
dc.description.abstractThe stimulation of hepatic glycogenesis is a ubiquitous response to a glucose challenge and quantifying its contribution to glucose uptake informs its role in restoring euglycemia. Glycogenesis can be quantified with labeled water provided that exchange of glucose-6-phosphate hydrogen 2 (G6P-H2) and body water via glucose-6-phosphate isomerase, and exchange of positions 4, 5 and 6 hydrogens (G6P-H456) via transaldolase, are known. These exchanges were quantified in 24-h fasted rats (Rattus norvegicus; n=6) and 21-day fasted seabass (Dicentrarchus labrax; n = 8) by administration of a glucose load (2000 mg·kg−1) enriched with [U-2H7]glucose and by quantifying hepatic glycogen 2H-enrichments after 2 h (rats) and 48 h (seabass). Direct pathway contributions of the glucose load to glycogenesis were also estimated. G6P-H2 and body water exchange was 61 ± 1% for rat and 47 ± 3% for seabass. Transaldolase-mediated exchange of G6P-H456 was 5 ± 1% for rat and 10 ± 1% for seabass. Conversion of the glucose load to hepatic glycogen was significant in seabass (249 ± 54 mg·kg−1) but negligible in rats (12 ± 1 mg·kg−1). Preload plasma glucose levels were similar for seabass and rats (3.3 ± 0.7 and 4.4 ± 0.1 mmol·L−1, respectively) but post-load plasma glucose was significantly higher in seabass compared to rats (14.6 ± 1.8 versus 5.8 ± 0.3 mmol·L−1, p b 0.01). In conclusion, G6P-H2 and body water exchange is incomplete for both species and has to be accounted for in estimating hepatic glycogen synthesis and direct pathway activities with labeled water tracers. Transaldolase-mediated exchange is insignificant. Hepatic direct pathway glycogenesis plays a prominent role in seabass glucose load disposal, but a negligible role in the rat.por
dc.description.sponsorshipThe authors acknowledge the financial support from Fundação para a Ciência e a Tecnologia (FCT) in the form of a Ph.D. Fellowship to F.O.M.: SFRH/ BD/51194/2010, and Research Grants to J.G.J.: PTDC/EBB-BIO/ 098111/2008 & PTDC/SAU-MET/111398/2009. The NMR spectrometer is part of the National NMR Network and was purchased in the framework of the National Programme for Scientific re-equipment, contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and FCT.por
dc.language.isoengpor
dc.publisherElsevier Ltd.por
dc.rightsopenAccesspor
dc.subjectDirect pathwaypor
dc.subjectTransaldolasepor
dc.subjectGlycogenesispor
dc.subjectGluconeogenesispor
dc.subjectSeabasspor
dc.subjectRatpor
dc.titleDisposition of [U-2H7]glucose into hepatic glycogen in rat and in seabasspor
dc.typearticlepor
degois.publication.firstPage316por
degois.publication.lastPage322por
degois.publication.issue2por
degois.publication.titleComparative Biochemistry and Physiology, Part Apor
dc.relation.publisherversionhttp://www.sciencedirect.com/science/article/pii/S1095643313001839#por
dc.peerreviewedYespor
dc.identifier.doi10.1016/j.cbpa.2013.07.002-
degois.publication.volume166por
item.fulltextCom Texto completo-
item.grantfulltextopen-
item.languageiso639-1en-
Appears in Collections:FCTUC Ciências da Vida - Artigos em Revistas Internacionais
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