A mechanism of regulation of hepatic Fru 2,6-P2 concentration upon refeeding: Involvement of xylulose 5-P and cyclic-AMP

Ye Qi Liu, Kosaku Uyeda

Research output: Contribution to journalArticle

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Abstract

In order to determine the mechanism for delayed increase in Fructose 2,6-P2 in livers of refed rats, the time course of changes in various metabolites upon refeeding NIH or high sucrose diet was investigated. Kinetics of increase in Fructose 2,6-P2 and Xylulose 5-P were similar but different from hexose 6-P or glycogen in die livers of 48 h starved rats refed with NIH diet. The increase in the Fructose 2,6-P2 level was a result of a combination of changes in Fructose 6-P,2-kinase and Fructose 2,6-bisphosphatase activity ratios, indicating dephosphorylation of the bifunctional enzyme and decreased cAMP. A similar correlation between Fructose 2,6-P2 and Xylulose 5-P and dephosphorylation was observed with refeeding high sucrose diet and also with 16 h starved rats. These kinetic results are consistent with the idea that a specific protein phosphatase 2A, activated by Xylulose 5-P, dephosphorylates Fructose 6-P,2-kinase:Fructose 2,6-bisphosphatase and also decreased protein kinase A activity, resulting in increased hepatic Fructose 2,6-P2.

Original languageEnglish (US)
Pages (from-to)554-558
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume221
Issue number3
DOIs
StatePublished - Apr 25 1996

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ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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