[Structural metabolic processes in the skeletal muscle tissue of chick embryos administered actinomycin D]

The development of the skeletal muscle tissue has been studied cytophotometrically, electron microscopically and radioautographically at administration of actinomycin-D (0.2 mcg/g) to the 11- and 15-day-old chick embryos). Different character of restorative processes under the conditions when RNA synthesis is disturbed by actinomycin-D administration is noted: before morphologically distinguished myosatellites appear (before the 13th-14th day of embryogenesis) and after myosatellites appearance (from the 14th-15th day of development). Evidently, the myosatellites are the muscle cells resistive to certain external factors, they ensure an effective adaptation of the skeletal muscle tissue to unfavourable effects. When the satellite cells appear, the skeletal muscle tissue acquires a new quality as a dynamically stable cambial system.