INVOLVEMENT OF ATP ADP-ANTIPORTER IN FATTY ACID-INDUCED UNCOUPLING INRAT-LIVER MITOCHONDRIA/

Data on the involvement of the ATP/ADP-antiporter in fatty acid-induce d uncoupling in liver mitochondria and on the sensitivity of this unco upling to the ATP/ADP-antiporter inhibitor carboxyatractylate are cont radictory. In the present study it is shown that in liver mitochondria uncoupled by palmitic acid, pyridoxal 5-phosphate, diethyl pyrocarbon ate, and glutamate exert an additional recoupling effect in the presen ce of carboxyatractylate, this effect disappearing on uncoupling of th e mitochondria by FCCP. It was also found that ADP at micromolar conce ntrations exerts a more pronounced recoupling effect when ADP is added before palmitic acid, the subsequent carboxyatractylate recoupling ef fect being small. The results suggest that a decrease in endogenous AD P may be responsible for the increase in the sensitivity of fatty acid -induced uncoupling to carboxyatractylate. It is concluded that in liv er mitochondria the ATP/ADP-antiporter and other membrane carriers are involved in fatty acid-induced uncoupling.