Acylcarnitines in intermediary metabolism.

From the time of its discovery in 1905 until the first description of its deficiency in 1973, the role of carnitine in intermediary metabolism was decidedly vague. Identification of carnitine acyl transferases and their products, acylcarnitines, have paved the way to the confirmation of the importance of carnitine in the transfer of fatty acid CoAs into the mitochondrion for beta-oxidation and energy production. The elucidation of defects in fatty acid oxidation together with the concept of carnitine therapy in certain organoacidaemias have given a new meaning to the term acylcarnitine. Not only are these compounds of diagnostic importance, their formation may be part of a secondary carnitine depletion which may be brought about as a result of various medications. Recent evidence suggests that long-chain acylcarnitines are responsible for cardiac arrhythmias and other effects, both good and bad, will certainly be found. This review will attempt to highlight the importance of acylcarnitines, from their production, the difficulties in analysis, the diagnostic possibilities and their positive and negative effects on intermediary metabolism.