Altered membrane association of glycogen phosphorylase in the dystrophic chicken.

The subcellular distribution of glycogen phosphorylase in pectoralis muscle from normal and dystrophic chickens was determined as a function of age. A substantially larger proportion of the total activity was associated with membranous cellular organelles, both mitochondria and sarcoplasmic reticulum, in preparations from dystrophic birds. The difference could be detected as early as 2 weeks ex ovo. Interaction of phosphorylase with cellular membranes may provide a probe for the underlying membrane defect in this dystrophy model.