Thyroxine Induced Transformation in Sarcoplasmic Reticulum of Rabbit Soleus and Psoas Muscles

Maria Tereza Nunes, Antonio Carlos Bianco, Andrea Migala, Bruno Agostini, Wilhelm Hasselbach

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The properties of the sarcoplasmic reticulum membranes isolated from slow-twitch type I soleus and fast-twitch type II psoas muscles of control and thyroxine treated rabbits were comparatively studied. Membrane yield, maximal calcium storing capacity, ATP-supported calcium uptake, calcium-dependent ATPase activity and calcium-dependent phosphoprotein formation were found to be 3-10 fold higher in psoas than in soleus preparations. Membrane yield, calcium-dependent ATPase activity, ATP-supported calcium transport and calcium-dependent phosphoprotein are at least twice enhanced in the membranes from soleus muscles of animals treated for 14-21 days with thyroxine. The corresponding capacities of the membranes from psoas muscles are not further augmented by the same thyroxine treatment. The maximal calcium storing capacity of the psoas membranes is their sole specific property which is significantly increased. The changes in the properties of the soleus muscles' sarcoplasmic reticulum membranes are engendered by an increase from 5 to 30-50% in the number of type II fibres. Since the calcium transporting properties of the sarcoplasmic reticulum membranes from type II fibres qualitatively differ from those of type I fibres, thyroxine does not only affect quantitative but also qualitative parameters of the muscles' sarcoplasmic reticulum membrane system.

Original languageEnglish (US)
Pages (from-to)726-734
Number of pages9
JournalZeitschrift fur Naturforschung - Section C Journal of Biosciences
Issue number9-10
StatePublished - Aug 1 1985


  • Fast and Slow Twitch Muscles
  • Sarcoplasmic Reticulum
  • Thyroxine

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


Dive into the research topics of 'Thyroxine Induced Transformation in Sarcoplasmic Reticulum of Rabbit Soleus and Psoas Muscles'. Together they form a unique fingerprint.

Cite this