title: Calcium-dependent activation of glycogen phosphorylase in rat pheochromocytoma PC12 cells by nerve growth factor.
abstract: Glycogen phosphorylase in PC12 cells exists in two forms analogous to those found in brain and muscle. The active phosphorylated form of the enzyme, phosphorylase-a, represents about 20-30% of total glycogen phosphorylase in these cells. Incubation of PC12 cells with 100 ng 7S nerve growth factor/ml increased phosphorylase-a within minutes. In contrast to nerve growth factor, insulin (6 ng/ml) and epidermal growth factor (6 ng/ml) decreased phosphorylase-a. Activation of phosphorylase-a by nerve growth factor was not accompanied by increases in cyclic AMP; however, removal of extracellular Ca2+ or incubation of cells with calcium channel blockers inhibited activation of glycogen phosphorylase by nerve growth factor.
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000201:enzymology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002460:Cell Line; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D009414:Nerve Growth Factors / Q000494:pharmacology*; D010673:Pheochromocytoma / Q000201:enzymology*; D010762:Phosphorylase a / Q000378:metabolism; D006005:Phosphorylases / Q000378:metabolism*; D051381:Rats
chemical_list: D007328:Insulin; D009414:Nerve Growth Factors; D004815:Epidermal Growth Factor; D010762:Phosphorylase a; D006005:Phosphorylases; D002118:Calcium