Activation of glycogen phosphorylase and glycogenolysis in rat skeletal muscle by AICAR--an activator of AMP-activated protein kinase.
We determined whether the cell permeable molecule AICAR, whose metabolite activates AMP-activated protein kinase (AMPK) in cells, affected glycogen metabolism in rat soleus muscle preparations in vitro. The basal and insulin-stimulated rates of radiochemical lactate formation, net lactate release and glycogen synthesis were determined. AICAR stimulated net lactate release (but not radiochemical lactate formation) only at a basal concentration of insulin. An increased rate of glycogenolysis was the likely cause of increased net lactate release as glycogen phosphorylase activity was significantly increased by AICAR. AICAR-stimulated net lactate release and phosphorylase activity were potently inhibited by insulin.
Young
M E
ME
Department of Biochemistry, University of Oxford, U.K.
Radda
G K
GK
Leighton
B
B
D055372:AMP-Activated Protein Kinases; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D006003:Glycogen / Q000096:biosynthesis / Q000378:metabolism*; D006019:Glycolysis; D007328:Insulin / Q000494:pharmacology; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D006005:Phosphorylases / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D051381:Rats; D017208:Rats, Wistar; D012265:Ribonucleotides / Q000494:pharmacology*
D007328:Insulin; D007773:Lactates; D009097:Multienzyme Complexes; D012265:Ribonucleotides; D019344:Lactic Acid; D000620:Aminoimidazole Carboxamide; D000249:Adenosine Monophosphate; D006003:Glycogen; D006005:Phosphorylases; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide