Ribosome biogenesis is activated during the early period of resistance training in rat skeletal muscle

Abstract

Resistance training (RT) induces skeletal muscle hypertrophy. Recently, it has been suggested that ribosome biogenesis plays an important part in RT‐induced skeletal muscle hypertrophy. However, influence of number of RT bouts is unclear.PurposeThe present study aimed to investigate the change of ribosomal RNA (rRNA) and ribosome protein content with changing the number of RT bouts.MethodMale Sprague‐Dawley rats were randomly assigned into six groups: Control (Cont), resistance‐trained with 1bout (1B), 2bouts (2B), 3bouts (3B), 6bouts (6B) and 18bouts(18B). RT protocol consisted of 50 repetitions of maximal isometric contraction of the gastrocnemius muscle by direct electric stimulation. Groups other than 1B performed 3 bouts of training per week. Muscle samples were collected 3h, 6h and 48h after the final exercise session in 1B to 3B, and 48h after the final exercise session in 6B and 18B.ResultsThe content of 18S+28S rRNA and rpS6 increased in 1B to 3B, but no significant difference was seen between 3B, 6B and 18B.ConclusionThe present showed that ribosome biogenesis is activated during the early period of RT. These results suggested that activation of ribosome biogenesis may contribute to increase protein synthesis during the later period, thereby leading to muscle hypertrophy.