TY - JOUR
T1 - A mechanism of regulation of hepatic Fru 2,6-P2 concentration upon refeeding
T2 - Involvement of xylulose 5-P and cyclic-AMP
AU - Liu, Ye Qi
AU - Uyeda, Kosaku
PY - 1996/4/25
Y1 - 1996/4/25
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0343831936&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0343831936&partnerID=8YFLogxK
U2 - 10.1006/bbrc.1996.0634
DO - 10.1006/bbrc.1996.0634
M3 - Article
C2 - 8629999
AN - SCOPUS:0343831936
SN - 0006-291X
VL - 221
SP - 554
EP - 558
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 3
ER -