Molybdate and tungstate act like vanadate on glucose metabolism in isolated hepatocytes.
In rat hepatocytes, molybdate and tungstate inactivate glycogen synthase by a mechanism independent of Ca2+ and activate glycogen phosphorylase by a Ca(2+)-dependent mechanism. On the other hand, both molybdate and tungstate increase fructose 2,6-bisphosphate levels and counteract the decrease in this metabolite induced by glucagon. These effectors do not directly modify 6-phosphofructo-2-kinase activity, even though they partially counteract the inactivation of this enzyme induced by glucagon. These effects are related to an increase on the glycolytic flux, as indicated by the increase in L-lactate and CO2 production and the decrease in glucose 6-phosphate levels in the presence of glucose. All these effects are similar to those previously reported for vanadate, although molybdate and tungstate are less effective than vanadate. These results could indicate that molybdate, tungstate and vanadate act on glucose metabolism in isolated hepatocytes by a similar mechanism of action.
Fillat
C
C
Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Autonomous University of Barcelona, Spain.
Rodríguez-Gil
J E
JE
Guinovart
J J
JJ
D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D002478:Cells, Cultured; D004789:Enzyme Activation; D005635:Fructosediphosphates / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006006:Glycogen Synthase / Q000187:drug effects / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008982:Molybdenum / Q000494:pharmacology*; D025481:Phosphofructokinase-2; D006005:Phosphorylases / Q000187:drug effects / Q000378:metabolism; D010770:Phosphotransferases / Q000378:metabolism; D051381:Rats; D014414:Tungsten / Q000494:pharmacology*; D017973:Tungsten Compounds; D014638:Vanadates / Q000494:pharmacology*
D005635:Fructosediphosphates; D007773:Lactates; D017973:Tungsten Compounds; C044659:molybdate; D002245:Carbon Dioxide; D019344:Lactic Acid; D014638:Vanadates; C027652:fructose 2,6-diphosphate; D008982:Molybdenum; D006005:Phosphorylases; D006006:Glycogen Synthase; D010770:Phosphotransferases; D025481:Phosphofructokinase-2; D005947:Glucose; C045951:tungstate; D014414:Tungsten