The fate of supplemental carnitine was studied in human subjects treated with drugs known to cause carnitine deficiency. Six children were treated with pivampicillin and equimolar l-carnitine for 7 days. On the last day of treatment, the plasma levels of total and free carnitine were decreased, but acylcarnitine levels were increased. A 12-fold increase in urinary excretion of acylcarnitines was found; it increased from 188.5 ± 82.7 to 2218.4 ± 484.1 μmole/day, and 84% was pivaloylcarnitine. Free carnitine excretion was reduced. Ten epileptic children on chronic valproate treatment received equimolar carnitine for a 2-week period. Plasma carnitine levels were elevated on the last day of treatment. A 3.4-fold increase in urinary acylcarnitines was found, but most of the excreted carnitines were free (64.5-fold increases). These data show that pivalate is readily converted to carnitine esters, in contrast to the limited conversion of valproate to acylcarnitines in humans.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism