Effect of triiodothyronine on cultured neonatal rat heart cells: Beating rate, myosin subunits and CK-isozymes

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of thyroid hormone on cell contractility, myosin subunit composition and creatine kinase activity was explored in cultured rat myocytes. Triiodothyronine (5 nm) was administered to neonatal rat heart myocytes grown in chemically defined medium. The hormone induced a 30% enhancement in the rate of cell beating and a complete transition from β-to α-myosin heavy chain synthesis. Myosin light chains as well as creatine kinase activity and isozymic distribution were unaffected by the hormone. The arrest of spontaneous contraction by either membrane depolarization or Ca2+ channel blockage did not interfere with the shift towards α-myosin heavy chain predominance. We conclude that thyroid regulation of myosin subunits is confined to the molecule heavy subunits and occurs irrespective of cell contraction. Furthermore, the genomic expression of creatine kinase is not regulated by thyroid hormone.

Original languageEnglish
Pages (from-to)649-655
Number of pages7
JournalJournal of Molecular and Cellular Cardiology
Volume20
Issue number7
DOIs
StatePublished - Jul 1988
Externally publishedYes

Keywords

  • Cell contractility
  • Chemically defined medium
  • Creatines kinase
  • Cultured myocytes
  • Myosin heavy chains
  • Myosin light chains
  • Triiodothyronine

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