L-carnitine is essential to beta-oxidation of quarried fatty acid from mitochondrial membrane by PLA(2)

Mol Cell Biochem. 2010 Sep;342(1-2):95-100. doi: 10.1007/s11010-010-0472-z. Epub 2010 May 5.


Mitochondrial beta-oxidation is an important system involved in the energy production of various cells. In this system, the function of L-carnitine is essential for the uptake of fatty acids to mitochondria. However, it is unclear whether or not endogenous respiration, ADP-induced O(2) consumption without substrates, is caused by L-carnitine treatment. In this study, we investigated whether L-carnitine is essential to the beta-oxidation of quarried fatty acids from the mitochondrial membrane by phospholipase A(2) (PLA(2)) using isolated mitochondria from the liver of rats. Intact mitochondria were incubated in a medium containing Pi, CoA and L-carnitine. The effect of L-carnitine treatment on ADP-induced mitochondrial respiration was observed without exogenous respiratory substrate. Increase in mitochondrial respiration was induced by treatment with L-carnitine in a concentration-dependent manner. Treatment with rotenone, a complex I blocker, completely inhibited ADP-induced oxygen consumption even in the presence of L-carnitine. Moreover, the L-carnitine dependent ADP-induced mitochondrial oxygen consumption did not increase when PLA(2) inhibitors were treated before ADP treatment. The L-carnitine-dependent ADP-induced oxygen consumption did contribute to ATP productions but not heat generation via an uncoupling system. These results suggest that L-carnitine might be essential to the beta-oxidation of quarried fatty acids from the mitochondrial membrane by PLA(2).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / pharmacology
  • Adenosine Triphosphate / metabolism
  • Animals
  • Carnitine / pharmacology*
  • Fatty Acids / chemistry*
  • Fatty Acids / metabolism
  • Male
  • Mitochondria, Liver / drug effects*
  • Mitochondria, Liver / metabolism
  • Mitochondrial Membranes / drug effects*
  • Mitochondrial Membranes / metabolism
  • Oligomycins / pharmacology
  • Oxidation-Reduction
  • Oxygen Consumption / drug effects
  • Phospholipases A2 / metabolism*
  • Rats
  • Rats, Wistar
  • Uncoupling Agents / pharmacology
  • Vitamin B Complex / pharmacology*


  • Fatty Acids
  • Oligomycins
  • Uncoupling Agents
  • Vitamin B Complex
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Phospholipases A2
  • Carnitine