Chronic stimulation of rat skeletal muscle induces coordinate increases in mitochondrial and nuclear mRNAs of cytochrome-c-oxidase subunits

Eur J Biochem. 1989 Feb 1;179(2):275-80. doi: 10.1111/j.1432-1033.1989.tb14551.x.

Abstract

Fast-twitch tibialis anterior muscle of the rat was subjected to chronic low-frequency (10 Hz, 10 h daily) nerve stimulation in order to investigate the time course of changes in cytochrome-c-oxidase activity, as well as in tissue levels of specific mitochondrially and nuclear-encoded, cytochrome-c-oxidase-subunit mRNAs. Chronic stimulation induced a progressive increase in cytochrome-c-oxidase activity which was threefold elevated after 35 days. A similar increase was recorded for citrate-synthase activity. Glyceraldehyde-3-phosphate dehydrogenase, which was studied as a glycolytic reference enzyme, moderately decreased, as did the tissue level of its corresponding mRNA. There was a parallel increase in the tissue levels of the two cytochrome-c-oxidase-subunit mRNAs over the entire stimulation time course. The extent of increase (stimulated/control) was 2.4 +/- 0.3 and 1.8 +/- 0.2 (means +/- SEM) for the mitochondrial and nuclear subunit mRNAs, respectively. This parallel increase suggested a coordinate regulation of the two subunits. The increase in cytochrome-c-oxidase activity initially corresponded to the changes at the mRNA level. However, with longer stimulation times (beyond 14 days), the increase in cytochrome-c-oxidase activity clearly exceeded that of the two mRNAs. This divergence was progressive and was interpreted to indicate that the increase in cytochrome-c-oxidase content was brought about not only by changes in the levels of the specific mRNAs, but also by alterations at the level of translation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Nucleus / enzymology*
  • Citrate (si)-Synthase / metabolism
  • DNA Probes
  • Electric Stimulation
  • Electron Transport Complex IV / genetics
  • Electron Transport Complex IV / metabolism*
  • Energy Metabolism
  • Glyceraldehyde-3-Phosphate Dehydrogenases / metabolism
  • Male
  • Mitochondria, Muscle / enzymology*
  • Muscles / enzymology*
  • Muscles / physiology
  • Nucleic Acid Hybridization
  • Protein Biosynthesis
  • RNA, Messenger / metabolism*
  • Rats
  • Rats, Inbred Strains

Substances

  • DNA Probes
  • RNA, Messenger
  • Glyceraldehyde-3-Phosphate Dehydrogenases
  • Electron Transport Complex IV
  • Citrate (si)-Synthase