Please use this identifier to cite or link to this item:
|Title:||Disposition of [U-2H7]glucose into hepatic glycogen in rat and in seabass||Authors:||Martins, Fátima O.
Pardal, M. A.
Macedo, M. Paula
Jones, John G.
|Keywords:||Direct pathway; Transaldolase; Glycogenesis; Gluconeogenesis; Seabass; Rat||Issue Date:||2013||Publisher:||Elsevier Ltd.||Serial title, monograph or event:||Comparative Biochemistry and Physiology, Part A||Volume:||166||Issue:||2||Abstract:||The 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.||URI:||http://hdl.handle.net/10316/25738||DOI:||10.1016/j.cbpa.2013.07.002||Rights:||openAccess|
|Appears in Collections:||FCTUC Ciências da Vida - Artigos em Revistas Internacionais|
Show full item record
Files in This Item:
|1-s2.0-S1095643313001839-main(1).pdf||340.11 kB||Adobe PDF||View/Open|
checked on Nov 8, 2019
WEB OF SCIENCETM
checked on Nov 7, 2019
checked on Jan 23, 2020
checked on Jan 23, 2020
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.