Anesthetics and cardiocentesis increase urinary carnitine excretion in rats and guinea pigs

Our interest in carnitine homeostasis lead us to determine effects of sever al commonly used anesthetics and blood sampling procedures on serum and uri nary carnitine concentrations. Serum and urine samples were collected from male rats and guinea pigs prior to and after anesthesia with and without ca rdiocentesis and assayed for carnitine and acylcarnitine. Methoxyflurane al one increased urinary carnitine excretion in guinea pigs but not in rats, M ethoxyflurane plus cardiocentesis increased urinary carnitine and acylcarni tine in both species, and isoflurane mimicked methoxyflurane in rats. Cardi ocentesis with phenobarbital or pentobarbital increased carnitine and acylc arnitine in serum but not in urine. Ketamine plus acepromazine increased to tal carnitine only in the serum of rats. A combination of ketamine and xyla zine increased serum carnitine and urinary acylcarnitine. It is concluded t hat anesthesia and cardiocentesis increased serum and urinary carnitine and acylcarnitines differently depending on the species and the anesthetic adm inistered. (C) 2001 Elsevier Science Inc. All rights reserved.