Role of fructose 2,6-bisphosphate in the stimulation of glycolysis by anoxia in isolated hepatocytes.
1. Incubation of hepatocytes from fed or starved rats with increasing glucose concentrations caused a stimulation of lactate production, which was further increased under anaerobic conditions. 2. When glycolysis was stimulated by anoxia, [fructose 2,6-bis-phosphate] was decreased, indicating that this ester could not be responsible for the onset of anaerobic glycolysis. In addition, the effect of glucose in increasing [fructose 2,6-bisphosphate] under aerobic conditions was greatly impaired in anoxic hepatocytes. [Fructose 2,6-bisphosphate] was also diminished in ischaemic liver, skeletal muscle and heart. 3. The following changes in metabolite concentration were observed in anaerobic hepatocytes: AMP, ADP, lactate and L-glycerol 3-phosphate were increased; ATP, citrate and pyruvate were decreased: phosphoenolpyruvate and hexose 6-phosphates were little affected. Concentrations of adenine nucleotides were, however, little changed by anoxia when hepatocytes from fed rats were incubated with 50 mM-glucose. 4. The activity of ATP:fructose 6-phosphate 2-phosphotransferase was not affected by anoxia but decreased by cyclic AMP. 5. The role of fructose 2,6-bisphosphate in the regulation of glycolysis is discussed.
D000693:Anaerobiosis; D000818:Animals; D005635:Fructosediphosphates / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D006019:Glycolysis / Q000187:drug effects; D006598:Hexosediphosphates / Q000378:metabolism*; D066298:In Vitro Techniques; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010732:Phosphofructokinase-1 / Q000378:metabolism; D051381:Rats; D013217:Starvation; D013268:Stimulation, Chemical
D005635:Fructosediphosphates; D006598:Hexosediphosphates; D007773:Lactates; D019344:Lactic Acid; C027652:fructose 2,6-diphosphate; D010732:Phosphofructokinase-1; D005947:Glucose