Turnover of fatty acids in rat liver cardiolipin: comparison with other mitochondrial phospholipids

Following intraperitoneal administration of 1-14C-linoleic acid or 2-3H-acetate to rats, the specific radioactivities of both liver cardiolipin and other mitochondrial phospholipids after different time intervals were measured. Comparison of the data obtained with those from another stock of rats treated with 32P-phosphate or 2-3H-glycerol showed that the fatty acids of cardiolipin, like those of other phospholipids, exhibit an independent turnover with respect to the remaining parts of the molecule. The half-life of acyl moieties of cardiolipin is ca. 20% higher than that of the same components of other mitochondrial phospholipids. Moreover, it appears that, in both cardiolipin and other phospholipids, linoleyl residues turn over faster than nonessential fatty acids. Discussion is made as to whether this characteristic can be related to the role of phospholipids in the functioning of some enzymes bound to the inner mitochondrial membrane.