Endotoxin increases the liver fructose 2,6-bisphosphate concentration in fasted rats.
Following endotoxin administration to fasted rats, the liver fructose 2,6-bisphosphate level is significantly increased within 1 hr, is elevated 2.3-fold by 3 hrs, and remains elevated 2 to 3-fold for at least 24 hrs. This increase in the potent allosteric activator of phosphofructokinase occurs when there is no change in the liver Glc 6-P, glycogen or cAMP concentrations, or in the activities of phosphoenolpyruvate carboxykinase or pyruvate kinase. The increase in fructose 2,6-bisphosphate concentration accounts for the increased phosphofructokinase activity previously observed in hepatocytes isolated 18 hours following endotoxin administration to rats (1). By stimulating the phosphofructokinase/Fru 1,6-bisphosphate cycle in the direction of glycolysis, fructose 2,6-bisphosphate is likely the factor responsible for decreased gluconeogenesis in endotoxemia.
Miller
B C
BC
Biochemistry Department, University of Texas, Southwestern Medical Center, Dallas.
Ishikawa
E
E
Uyeda
K
K
Cottam
G L
GL
D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D004731:Endotoxins / Q000494:pharmacology*; D004789:Enzyme Activation; D005215:Fasting; D005635:Fructosediphosphates / Q000378:metabolism*; D019298:Glucose-6-Phosphate; D005958:Glucosephosphates / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D006019:Glycolysis; D006598:Hexosediphosphates / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism; D010732:Phosphofructokinase-1 / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012485:Salmonella typhi
D004731:Endotoxins; D005635:Fructosediphosphates; D005958:Glucosephosphates; D006598:Hexosediphosphates; D019298:Glucose-6-Phosphate; C027652:fructose 2,6-diphosphate; D006003:Glycogen; D000242:Cyclic AMP; D010732:Phosphofructokinase-1; D011770:Pyruvate Kinase; D010729:Phosphoenolpyruvate Carboxykinase (GTP); C029063:fructose-1,6-diphosphate