Dexamethasone effects on creatine kinase activity and insulin-like growth factor receptors in cultured muscle cells

P. A. Whitson, C. A. Stuart, M. H. Huls, C. F. Sams, Nitza Cintron

Research output: Contribution to journalArticle

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Abstract

We examined the effects of dexamethasone on creatine kinase (CK) activity and insulin-like growth factor I (IGF-I) binding in two skeletal muscle-derived cell lines (mouse, C2C12; rat, L6) and in one cardiac muscle-derived cell line (rat, H9c2). Dexamethasone treatment during differentiation of cultured cells caused a dose-dependent increase in CK activity as well as an increase in the degree of myotube formation in C2C12 and L6, whereas H9c2 cells did not exhibit significant CK activities during culture or dexamethasone treatment. Dexamethasone treatment of C2C12 did not stimulate proliferation in differentiating cultures, but a dose-dependent increase in the number of nuclei was observed for L6 concomitant with increased CK activity. In L6 the increased CK activity may therefore reflect a dose-dependent increase in proliferation. Short-term (48 hr) treatment of C2C12 with dexamethasone (20 nM) did not appear to alter myoblast fusion but reversibly increased CK activity. In C2C12 the observed increase in CK, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activities with dexamethasone treatment suggest modulation of protein expression and/or turnover. Although the data for dexamethasone effects on CK activities varied in each of the cell lines, consistent behavior was observed in all three cell lines when IGF-I 24 binding was examined. IGF-I binding to dexamethasone-treated cells (50 nM for 24 hr the day prior to confluence) resulted in an increased number of available binding sites, with no effect on the binding affinities. Affinity cross linking and autoradiography indicated that the increase in IGF-I binding was the result of dexamethasone up-regulation of type I IGF receptors. Our data for all three muscle cell lines suggest that similar heterologous hormone receptor modulation of type I IGF receptor sites occurs with dexamethasone treatment.

Original languageEnglish (US)
Pages (from-to)8-17
Number of pages10
JournalJournal of Cellular Physiology
Volume140
Issue number1
StatePublished - 1989
Externally publishedYes

Fingerprint

Somatomedin Receptors
Creatine Kinase
Muscle Cells
Dexamethasone
Muscle
Cultured Cells
Cells
Insulin-Like Growth Factor I
Cell Line
IGF Type 1 Receptor
Rats
Modulation
Myoblasts
Skeletal Muscle Fibers
Aspartate Aminotransferases
Autoradiography
Alanine Transaminase
Cardiac Myocytes
Skeletal Muscle
Up-Regulation

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

Cite this

Dexamethasone effects on creatine kinase activity and insulin-like growth factor receptors in cultured muscle cells. / Whitson, P. A.; Stuart, C. A.; Huls, M. H.; Sams, C. F.; Cintron, Nitza.

In: Journal of Cellular Physiology, Vol. 140, No. 1, 1989, p. 8-17.

Research output: Contribution to journalArticle

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