ABSORPTION AND EXCRETION OF L-CARNITINE DURING SINGLE OR MULTIPLE DOSINGS IN HUMANS

Changes of short-chain (free) and long-chain (acyl) carnitine activity (CA) in plasma, whole blood, red blood cells (rbc) and urine were ind uced (a) by ingestion of L-carnitine as a single dose of 500 mg, or 25 00 mg, or (b) by ingestion of a daily dose of 2500 mg for 10 days. A s ingle 500-mg dose induced insignificant increases of CA in blood const ituents. However elevated free CA was noted in urine. Single or daily high doses - e.g. 2500 mg of carnitine - significantly increased free and acyl-CA in plasma, whole blood and urine, but these increases were low. Variations in dosage or frequency of carnitine intake led to no changes in rbc CA; presumably CA in plasma diffused only slowly into r bc. The apparent low absorption of carnitine suggests that oral therap y may not effect rapid repletion of body stores of CA.