The effect of L-carnitine-supplemented total parenteral nutrition on tissue amino acid concentrations in piglets.

Miniature piglets underwent total parenteral nutrition (TPN) with and without L-carnitine supplementation during a 7-day period. Thereafter the tissue amino acid concentrations of liver, heart, skeletal muscle and brain were determined and compared to those of orally fed animals. The altered tissue amino acid concentrations during TPN without carnitine returned to normal when L-carnitine was supplemented. The most striking changes of tissue concentrations showed taurine in liver, muscle and brain and ethanolamine in heart and brain. In muscle the branched-chain amino acids were increased when L-carnitine was added to the TPN regime. Ethanolamine changes were discussed with respect to the position of this amino acid in the synthesis of phospholipids. The marked decrease of brain taurine concentrations after carnitine-free TPN was accompanied by reduced values for GABA. Both the substances function as inhibitory transmitters in the brain and should be considered when seizure activity in patients with systemic carnitine deficiency is discussed.