Biochemical and histochemical studies on skeletal muscle in rat during the course of development. The biochemical properties of type 2C muscle fiber.

1. Biochemical and histochemical analyses were performed on skeletal rat muscles over the course of development from neonate to adult. 2. A small amount of triglyceride and a large amount of glycogen were found to be contained in neonatal type 2C muscle fiber; based on this finding the main energy metabolism in this fiber was thought to be anaerobic glycolysis. 3. Moreover at 10 days type 2C muscle fiber was shown to contain a large amount of triglyceride. 4. These results suggest that, although histochemical characteristics remain the same, biochemical properties change during the course of muscle development.