Glycogen-enzymes containing bodies in type 2 fibres of tenotomized muscles in the rat

Inclusion bodies containing glycogen-enzymes were found in 30 to 60% of type 2 fibres of tenotomized calf muscles (m. gastrocnemius, m. soleus, m. plantaris) in rats, using histochemical reactions. The bodies appeared within 1 week after the tenotomy and were localized both in the central and the subsarcolemmal regions and rarely extruded into the extracellular space. These aggregates are 3 to 15 microns in length and 2 to 11 microns in diameter. In addition to glycogen, these bodies also contained various enzymes of the glycogen metabolism such as phosphorylase, a branching enzyme, and glucose-6-phosphatase, but showed no NADH-reductase, lactate dehydrogenase, or myofibrillar ATP-ase activity. The results indicate that glycogen-enzymes containing bodies are a degenerative phenomenon, which occurs only in type 2 fibres of the tenotomized muscles.