Plasma and urine carnitine in children with diabetes mellitus.

L-Carnitine is essential for the transport of long chain fatty acids into mitochondria and, hence, in ketoacid production. Total, free and acylcarnitine in plasma and urine have been determined in 52 children and adolescents with insulin-dependent juvenile diabetes and compared with 72 controls. The subjects were divided into three age groups 8-10, 11-15 and 16-20 years. The plasma, total and free carnitine were significantly lower in diabetic patients than in controls in all age groups. Acylcarnitine was significantly higher in the diabetic patients than in the controls in the two younger age groups. No sex-related differences in plasma carnitine and its derivatives were found in the two younger groups. A statistically significant correlation coefficient was noted between glycosylated hemoglobin and the plasma acyl/free carnitine ratio, 2 p less than 0.05. The daily urinary excretion and renal clearance of carnitine and its derivatives showed few significant differences between the diabetic and the control subjects.