Dexamethasone regulates the actions of endogenous insulin-like growth factor-II during myogenic differentiation.
The effect of dexamethasone (DEX) on the action of endogenous insulin-like growth factor (IGF)-II during myogenic differentiation was investigated by culturing C2C12 mouse myogenic cells in serum-free medium. DEX treatment maintained a high level of creatine kinase (CK) activity, and caused an increase in the number of nuclei per cell, hypertrophy and IGF-II mRNA accumulation in the cells. These effects were abrogated by the glucocorticoid receptor antagonist RU-38486. An anti-IGF-II monoclonal antibody neutralized DEX-dependent CK activity. Thus, we conclude that DEX increases the level of IGF-II mRNA in C2C12 cells, and that DEX may assist myogenic differentiation via, at least in part, its promotive action on IGF-II gene expression.
Department of Oral Anatomy, Hiroshima University School of Dentistry, Japan.
Y
Y
Yoshiko
K
K
Hirao
N
N
Maeda
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D003907:Dexamethasone / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology*; D006727:Hormone Antagonists / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis / Q000502:physiology*; D051379:Mice; D015735:Mifepristone / Q000494:pharmacology; D018482:Muscle, Skeletal / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D016895:Culture Media, Serum-Free; D005938:Glucocorticoids; D006727:Hormone Antagonists; D012333:RNA, Messenger; D015735:Mifepristone; D007335:Insulin-Like Growth Factor II; D003907:Dexamethasone