Effects of Corticosterone on Ca^<2+> Uptake and Myofibrillar Disassembly in Primary Muscle Cell Culture(Biochemistry & Molecular Biology)

概要

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This study was done to examine the effects of corticosterone, a glucocorticoid, on Ca^<2+> uptake, proteolysis, and Ca^<2+> channels in primary cultures of chick muscle cells, to clarify the mechanism of glucocorticoid action on muscle proteolysis. Chick muscle cells were incubated for 24 h in a medium containing corticosterone (30 ng/ml) when the cells were confluent (6 days). To examine the contribution of Ca^<2+> channels, nifedipine, a Ca^<2+> channels antagonist, was used. Ca^<2+> uptake measured with ^<45>CaCl_2 was increased three-fold by corticosterone, with a peak at 12 h after the treatment started. The growth of the cells estimated from the protein content and creatine kinase activity was not affected by corticosterone. Proteolysis, evaluated with [^3H] tyrosine as a label of the protein and N^τ-methylhistidine release, was unchanged by corticosterone. However, the amount of easily releasable myofilament as a measure of myofibrillar disassembly in the muscle cells was increased by corticosterone, and prevented by nifedipine. These results show that corticosterone increases Ca^<2+> uptake and starts myofibrillar protein breakdown.
社団法人日本農芸化学会の論文
2003-02-23