Comparative acute effects of l-carnitine and dl-carnitine on hepatic catabolism of l-alanine and l-glutamine in rats

Acta Pharmacol Sin. 2004 Oct;25(10):1257-61.

Abstract

Aim: To compare the acute effects of l-carnitine (LCT) and dl-carnitine (DLC) on hepatic catabolism of l-alanine and l-glutamine in rats.

Methods: Livers from 24 h fasted and fed rats were perfused in situ. The substrates l-alanine (5 mmol/L) and l-glutamine (5 mmol/L) were employed. The gluconeogenic and ureogenic activity was measured as the difference between the rates of glucose and urea released during and before the infusion of l-glutamine or l-alanine.

Results: LCT (60 micromol/L) but not DLC (60 micromol/L and 120 micromol/L) increased the production of glucose and urea from l-glutamine. However, neither LCT (60 micromol/L and 120 micromol/L) nor DLC (60 micromol/L and 240 micromol/L) showed any significant effect on hepatic glucose and urea production from l-alanine.

Conclusion: The results showed a different acute effect of LCT and DLC on the activation of hepatic gluconeogenesis and ureagenesis promoted by l-glutamine, reinforcing the idea that DLC could not replace LCT.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine / metabolism*
  • Animals
  • Carnitine / pharmacology*
  • Gluconeogenesis / drug effects
  • Glucose / biosynthesis
  • Glutamine / metabolism*
  • Liver / metabolism*
  • Male
  • Rats
  • Rats, Wistar
  • Stereoisomerism
  • Urea / metabolism

Substances

  • Glutamine
  • Urea
  • Glucose
  • Alanine
  • Carnitine