[Induction of mitochondrial volume changes by homologous O-acyl carnitines]

The volume changes of isolated rat liver mitochondria induced by O-acylcarnitines are dependent on the optical isomery and the length of the apolar hydrogen chain in the acyl residue. Within the homologous series of the straight-chain O-acyl carnitines the swelling-inducing effect increases from decanoyl carnitine to the palmitoyl carnitine. The contraction is observed only under the effect of O-acylL(--)carnitines, while isomers add up in their swelling-inducing effect. The surface activity of the O-acyl carnitines increases with increasing chain length, and the critical micellar concentration decreases logarithmically. The comparison of the tenside properties with the swelling- and contraction-inducing effects shows that the swelling is brought about by hydrophobic interactions with the membranes, while the contraction is the consequence of energy-dependent metabolic processes which are connected with the influx of acyl carnitines and the efflux of the ions from the mitochondria.