Assay Methods
Samples for carnitine analysis were obtained from
subjects at rest, after an overnight fast. Three blood
samples (5 ml each) were drawn, the samples centrifuged
at 600g for 3 minutes in chilled centrifuge tubes,
and plasma aliquots stored at -70° C. Carnitine was
measured by a radioenzymatic assay as previously
described. Plasma samples were prepared in perchloric
acid for the determination of free carnitine and
short-chain acylcarnitines (acyl groups less than 10
carbon atoms). Total acid soluble carnitine concentration
refers to the sum of the free carnitine and
short-chain acylcarnitine concentrations. The ratio of
short-chain acylcarnitine concentration to total acid
soluble carnitine concentration was also calculated
from these measurements. Each assay was performed
in duplicate, and the measurements from the three
plasma samples were averaged to determine resting
values. In three treated subjects, carnitine measurements
were not made (one due to technical problems
with blood drawing and two because they were not
fasting at the time of the measurement).