Palmitoyl carnitine: an endogenous promotor of calcium efflux from rat heart mitochondria.
The effects of the fatty acid ester palmitoyl carnitine (PC) on mitochondrial Ca2+ handling and ATP synthesis are described. At low concentrations (5-40 microM) PC was found to produce changes in mitochondrial Ca2+ handling, the most significant effect (P less than 0.05) being the promotion of Ca2+ efflux (EC25 = 1.19 +/- 0.11 microM). Studies on mitochondrial substrate oxidation in the presence of either glutamate plus malate, or succinate, confirmed the ability of PC (10-100 microM) to cause loss of respiratory control as shown by reductions in the Respiratory Control Index for each substrate. It was concluded that the effect of PC on Ca2+ transport was due to a direct action on the Na+-Ca2+ antiporter system, whilst the effect on respiration was due to an uncoupling action.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002331:Carnitine / Q000031:analogs & derivatives*; D005260:Female; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D008293:Malates / Q000378:metabolism; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010172:Palmitoylcarnitine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid
D005971:Glutamates; D008293:Malates; D013386:Succinates; D009243:NAD; D010172:Palmitoylcarnitine; D018698:Glutamic Acid; C030298:malic acid; D019802:Succinic Acid; D002331:Carnitine; D002118:Calcium