Time course of changes in protein synthesis in marcaine-induced skeletal muscle regeneration.

The time course of the regeneration of rat skeletal muscle has been examined after injection of the myotoxic drug, Marcaine, to induce regeneration. Muscle wet weight decreases during the initial phase of the regeneration process while the ability of the regenerating muscle to incorporate [35S]methionine into protein, the yield and activity of muscle polysomes and the yield of total and poly(A) + RNA all increase initially. Following the initial changes, these parameters return to near control values by 30 days after Marcaine injection. Theoretical calculations suggest that the changes in polysome yield and activity are sufficient to account for the changes in the ability of muscle fragments to synthesize protein during the regeneration process. The specific activity of total muscle RNA in the wheat germ cell-free system decreases initially during the early stages of the regeneration process. This decrease may reflect the fact that while the yields of both total and poly(A) + RNA increase during the early stages of regeneration, the percentage of the total RNA which is poly(A) + decreases initially.