Urinary Profile of L-Carnitine and Its Derivatives in Starved Normal Persons and ACTH Injected Patients with Myopathy

Abstract

Effect of starvation or ACTH injection on the urinary level and profile of L-carnitine and its derivatives was studied in four healthy adult men or in a normal child and two patients with myopathy, respectively. Mean total L-camitine level in the control urine sample obtained before starvation was 389 � 34 /imol man day. The percentage distribution was found to be 46% for free-, 9% for acetyl- and 45% for acyl-L-camitine. The acyl-L-carnitine fraction contained short-chain (65%) and long-chain acyl-L-carnitine (35%). With 2-day starvation urinary excretion of free-L-camitine was slightly decreased and, in contrast, that of acetyl-L-carnitine was considerably increased, resulting in a significant increase in urinary total L-carnitine levels. Urinary excretion of acyl-L-carnitine was increased two-folds with starvation, but that of long-chain acyl-L-carnitine was not changed. In a normal child (female, 3.5 yr) and two patients (female, 4.5 yr and male, 23 yr) with myopathy, ACTH injection induced a significant elevation of urinary total L-carnitine levels, being mainly caused by an increased excretion of free-L-carnitine and, in the adult patient, acyl-L-carnitine. Muscle total L-carnitine contents were normal in two children but abnormally low in the adult patient, who had simultaneously very low urinary total L-carnitine level before ACTH injection. Thus, in the adult patient myopathy might be possibly caused in part by carnitine deficiency. Starvation and ACTH-induced changes in urinary level and profile of L-carnitine and its derivatives were discussed in relation to carnitine biosynthesis as well as renal regulation of carnitine clearance. © 1983, Center for Academic Publications Japan. All rights reserved.