title: Glycogen cycle enzymes and cyclic nucleotides in avian muscular dystrophy.
abstract: Fast-frozen pectoralis muscle samples were taken from normal chickens (lines 200 and 412) and chickens having hereditary muscular dystrophy (line 304). The glycogen phosphorylase activity ratio (activity without AMP/activity with AMP) was significantly greater in dystrophic muscles (0.306 +/- 0.046) than it was in normal muscles (0.090 +/- 0.023). Glucagon treatment did not cause any changes in phosphorylase activity ratios. Isoproterenol treatment of both normal and dystrophic muscles raised the phosphorylase activity ratio of normal muscles to 0.446 +/- 0.054, which was not significantly different from that of the dystrophic muscles. The dystrophic muscles had significantly less glycogen than normal muscles (23.3 +/- 2.8 compared with 36.8 +/- 2.8 mumoles glucosyl units/g of muscle). There was no relationship of muscular dystrophy to total phosphorylase activity (measured in the presence of 1 mM AMP) and to glycogen synthase activities measured without and with glucose 6-phosphate. Normal muscles had 28% less cAMP and 49% less cGMP than dystrophic muscles, but these differences were eliminated by treatment of the chickens with glucagon.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002645:Chickens; D000242:Cyclic AMP / Q000032:analysis; D006152:Cyclic GMP / Q000032:analysis; D005934:Glucagon; D006006:Glycogen Synthase / Q000378:metabolism; D007545:Isoproterenol; D009132:Muscles / Q000032:analysis / Q000201:enzymology / Q000378:metabolism*; D009137:Muscular Dystrophy, Animal / Q000378:metabolism*; D006005:Phosphorylases / Q000378:metabolism
chemical_list: D005934:Glucagon; D000242:Cyclic AMP; D006005:Phosphorylases; D006006:Glycogen Synthase; D000262:Adenylyl Cyclases; D006152:Cyclic GMP; D007545:Isoproterenol