title: Differential excretion of xenobiotic acyl-esters of carnitine due to administration of pivampicillin and valproate.
abstract: 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 mumole/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.
authors.affiliation: Department of Pediatrics, University Medical School of Pecs, Hungary.
authors.forename: B
authors.initials: B
authors.lastname: Melegh
authors.forename: J
authors.initials: J
authors.lastname: Kerner
authors.forename: V
authors.initials: V
authors.lastname: Jaszai
authors.forename: L L
authors.initials: LL
authors.lastname: Bieber
mesh_terms: D000293:Adolescent; D000328:Adult; D000667:Ampicillin / Q000031:analogs & derivatives*; D002331:Carnitine / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002648:Child; D002784:Cholesterol / Q000097:blood; D002849:Chromatography, Gas; D003920:Diabetes Mellitus / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D006885:Hydroxybutyrates / Q000378:metabolism; D008055:Lipids / Q000097:blood; D008297:Male; D010917:Pivampicillin / Q000378:metabolism*; D014280:Triglycerides / Q000097:blood; D014635:Valproic Acid / Q000378:metabolism*; D015262:Xenobiotics / Q000097:blood / Q000378:metabolism* / Q000652:urine
chemical_list: D005230:Fatty Acids, Nonesterified; D006885:Hydroxybutyrates; D008055:Lipids; D014280:Triglycerides; D015262:Xenobiotics; D010917:Pivampicillin; D014635:Valproic Acid; D000667:Ampicillin; D002784:Cholesterol; D002331:Carnitine