Evidence for suppression of hepatic glucose-6-phosphatase with carbohydrate feeding.

Journal Article (Journal Article)

The mechanism by which exogenous glucose stimulates the incorporation of hepatic glucose-6-phosphate into glycogen in fasted rats has not been clearly delineated. We gave glucose intragastrically over a 3.5-h period during which liver glycogen was deposited at linear rates. Simultaneous primed continuous infusion of [2-3H] or [3-3H]glucose established that under these conditions absolute carbon flow through hepatic glucose-6-phosphatase was greatly suppressed. After 1 h, hepatic [UDP-glucose] and [glucose-6-phosphate] had fallen by 50-60% and the former remained low throughout the experiment. By contrast, [glucose-6-phosphate] rebounded to its initial value by 2 h and remained at this level during the subsequent hour. We interpret the data as follows. Exogenous glucose, in addition to acting as a precursor of liver glucose-6-phosphate, causes diversion of the latter away from free glucose formation and into glycogen synthesis. The fall in [UDP-glucose] is in accord with a glucose-induced activation of glycogen synthase, as proposed by Hers (Annu. Rev. Biochem. 1976; 45:167-89.). However, the fall-rise sequence of glucose-6-phosphate concentration constitutes the first direct evidence in vivo for simultaneous inhibition at the level of glucose-6-phosphatase.

Full Text

Duke Authors

Cited Authors

  • Newgard, CB; Foster, DW; McGarry, JD

Published Date

  • February 1, 1984

Published In

Volume / Issue

  • 33 / 2

Start / End Page

  • 192 - 195

PubMed ID

  • 6319214

International Standard Serial Number (ISSN)

  • 0012-1797

Digital Object Identifier (DOI)

  • 10.2337/diab.33.2.192


  • eng

Conference Location

  • United States