Experimentally-Induced Muscle Atrophy in the Developing Chick Embryo: Glycogen Metabolism

Glycogen content and the activities of phosphorylase (PHRL) and glycogen synthetase (GS) in the hind limb muscle of normal, unilaterally (right) - denervated and in nicotine sulfate (NS) - injected chick embryos were determined to assess the effect of the experimental treatments on glycogen metabolism. Glycogen content increased with increase in age in normal limbs, remained relatively low in denervated limbs, increased with age in left (unoperated) limbs of denervated embryo limbs at a rate lower than normal except between days 13 and 17 of incubation, when glycogen content tripled. The same parameter in NS-injected embryo limbs remained generally low throughout development. Overall glycogen metabolism showed opposite patterns when a comparison was made between the two experimental groups. Comments are made on the relation of the results of this study to the effects of various muscle disorders