骨格筋の肥大、萎縮における筋内DNA、RNA、タンパク質レベルの影響 Effects of skeletal muscle hypertrophy and atrophy on muscle DNA, RNA and protein levels.

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Abstract

Skeletal muscles are capable of adapting themselves to a variety of exercise stimuli with varied changes in their mechanical and metabolic properties. Muscle hypertrophy is induced by stretching of matured muscles <I>in vivo</I>. On the contrary, muscle atrophy is induced by some models of reduced neuromuscular activity. However, little data are available for the intracellular changes of skeletal muscle hypertrophy and atrophy irrespective of a variety of techniques. Therefore, it is useful to use the <I>β</I><SUB>2</SUB>-agonist (clenbuterol : CLE)-induced muscle hypertrophy and whole body suspension (WBS)-induced muscle atrophy. Male SD rats were used and divided into the control (CON) groups and the CLE administered (ADM) or WBS groups. CLE (1<I>mg</I>/<I>kg</I> BW/<I>day</I>) was administered for 30 <I>days</I>. WBS was carried out for 10 <I>days</I>. SOL and GAS muscles were used for muscle RNA, DNA and protein assays. Protein/RNA ratios of both muscles increased by 16-19<I>%</I> in ADM group. Protein/DNA ratios of both muscles increased by 11-37<I>%</I> in ADM group. Protein/DNA ratios of both muscles decreased by 32-39<I>%</I> in WBS group. RNA/DNA ratios of both muscles decreased by 28-39<I>%</I> in WBS group. In conclusion, SOL muscle hypertrophy by CLE may be at least partly related to the increases in DNA transcription and protein synthesis (=RNA/DNA) and apparent cell volume (=Protein/DNA). WBS-induced muscle atrophy may be accompanied by the decreases in Protein/DNA ratio and RNA/DNA ratio without changing ribosomal capacity (=Protein/RNA). <b>[Jpn J Physiol 55 Suppl:S225 (2005)]</b>

Skeletal muscles are capable of adapting themselves to a variety of exercise stimuli with varied changes in their mechanical and metabolic properties. Muscle hypertrophy is induced by stretching of matured muscles <I>in vivo</I>. On the contrary, muscle atrophy is induced by some models of reduced neuromuscular activity. However, little data are available for the intracellular changes of skeletal muscle hypertrophy and atrophy irrespective of a variety of techniques. Therefore, it is useful to use the <I>β</I><SUB>2</SUB>-agonist (clenbuterol : CLE)-induced muscle hypertrophy and whole body suspension (WBS)-induced muscle atrophy. Male SD rats were used and divided into the control (CON) groups and the CLE administered (ADM) or WBS groups. CLE (1<I>mg</I>/<I>kg</I> BW/<I>day</I>) was administered for 30 <I>days</I>. WBS was carried out for 10 <I>days</I>. SOL and GAS muscles were used for muscle RNA, DNA and protein assays. Protein/RNA ratios of both muscles increased by 16-19<I>%</I> in ADM group. Protein/DNA ratios of both muscles increased by 11-37<I>%</I> in ADM group. Protein/DNA ratios of both muscles decreased by 32-39<I>%</I> in WBS group. RNA/DNA ratios of both muscles decreased by 28-39<I>%</I> in WBS group. In conclusion, SOL muscle hypertrophy by CLE may be at least partly related to the increases in DNA transcription and protein synthesis (=RNA/DNA) and apparent cell volume (=Protein/DNA). WBS-induced muscle atrophy may be accompanied by the decreases in Protein/DNA ratio and RNA/DNA ratio without changing ribosomal capacity (=Protein/RNA). <b>[Jpn J Physiol 55 Suppl:S225 (2005)]</b>

Journal

  • Proceedings of Annual Meeting of the Physiological Society of Japan

    Proceedings of Annual Meeting of the Physiological Society of Japan 2005(0), S225-S225, 2005

    PHYSIOLOGICAL SOCIETY OF JAPAN

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