Electrical stimulation inactivates muscle acetyl-CoA carboxylase and increases AMP-activated protein kinase

Am J Physiol. 1997 Feb;272(2 Pt 1):E262-6. doi: 10.1152/ajpendo.1997.272.2.E262.

Abstract

Muscle malonyl-CoA decreases during exercise or electrical stimulation, the exercise-induced decline being accompanied by changes in the kinetic properties [maximal velocity (Vmax), activation constant (Ka), and citrate concentration required to produce 50% Vmax (K0.5)] of acetyl-CoAcarboxylase (ACC) and by an increase in the AMP-activated protein kinase activity (AMPK). This study was designed to ascertain whether the exercise-induced changes are contraction mediated and, if so, to follow the time course of these changes. The left sciatic nerve of rats was stimulated at 1 Hz for 0, 2, 5, 10, 20, or 30 min, and the gastrocnemius-plantaris muscle group was then excised, frozen in liquid nitrogen, and later analyzed for malonyl-CoA and other metabolites. ACC and AMPK activities were quantitated in ammonium sulfate precipitates from homogenates prepared from the frozen muscles. The Vmax and Ka of ACC for citrate decreased and increased, respectively, over the first 10 min of stimulation, but significantly increased AMPK activity was not observed until 10 to 20 min of stimulation (P < 0.05). Stimulation increased estimated free AMP (P < 0.05). Thus exercise-induced changes in functional properties of ACC appear to be contraction mediated and are accompanied by increased AMPK activity and an increase in the estimated free AMP.

Publication types

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

MeSH terms

  • AMP-Activated Protein Kinases
  • Acetyl-CoA Carboxylase / metabolism*
  • Adenosine Monophosphate / metabolism
  • Adenosine Triphosphate / metabolism
  • Animals
  • Electric Stimulation
  • Male
  • Malonyl Coenzyme A / metabolism
  • Multienzyme Complexes / metabolism*
  • Muscle Contraction / physiology
  • Muscles / enzymology*
  • Protein Kinases / metabolism*
  • Protein-Serine-Threonine Kinases*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Multienzyme Complexes
  • Adenosine Monophosphate
  • Malonyl Coenzyme A
  • Adenosine Triphosphate
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • AMP-Activated Protein Kinases
  • Acetyl-CoA Carboxylase