The relationship of choline and carnitine in the choline deficient rat.

Levels of carnitine in choline deficient and choline supplemented rats were measured in heart, skeletal muscle, plasma, and liver after various treatments. A decreased hepatic concentration of carnitine was shown to be closely correlated to the deficiency in dietary choline. No change in the concentration of plasma ketone bodies after a 48 hour fast was observed in the choline deficient rats when compared to choline supplemented controls, even though the level of hepatic carnitine subsequent to the fast was lower in the deficient rats. The concentration of hepatic carnitine was increased to normal values 1.5 hours after a single injection of 100 mumoles of choline, but was not affected by other "methyl" donors. From experiments presented in this communication it is concluded that the increase in hepatic carnitine is probably due to increased transport and uptake of this compound into the liver rather than by "de novo" synthesis.