Entry of acetyl-L-carnitine into biosynthetic pathways.

[1-14C]Acetyl-L-carnitine was injected into fed and fasted mice and the time-course of distribution of 14C in various tissues and tissue components was determined. The major product was 14CO2. However, considerable quantities of radioactivity were localized in liver with much smaller quantities in heart, brain, skeletal muscle and kidney. Most of the 14C in liver was located in the fatty acids of phospholipids and triacylglycerols within 10 min after injection. The data demonstrate that the acetyl moiety of acetylcarnitine rapidly enters lipid biosynthetic pools in liver.