Carnitine blood concentrations and fat utilization in parenterally alimented premature newborn infants

To investigate the relationships among carnitine intake, carnitine blood concentrations, and the ability to utilize exogenous fat, total carnitine, free carnitine, acylcarnitine, beta-hydroxybutyrate, free fatty acid and triglyceride plasma concentrations were measured in 26 parenterally alimented appropriate-for-gestational-age premature infants before and at the end of a four-hour infusion of Intralipid, 1 gm/kg body weight. There was an increase in plasma levels of AC, BOB, FFA, and TG, but a decrease of FC, TC was unaffected by the infusion, but strongly correlated with calculated carnitine intake. At the end of the fat infusion, AC and BOB were positively correlated, and FFA negatively correlated with TC. The results demonstrate the proportion of AC to FC to be an additional indicator of fatty acid utilization and suggest that decreased carnitine intake in premature infants may impair fatty acid oxidation and ketogenesis.