L-carnitine and carnitine ester transport in the rat small intestine.

ABSTRACT

L-carnitine and its esters (acetyl-L-carnitine and propionyl-L-carnitine) at pharmacological doses (1, 5 and 10 mM) are absorbed by the rat jejunum by simple diffusion. Partition coefficients of carnitine esters determined in lipophilic media (diethyl ether/water and olive oil/water) are greater than that of L-carnitine. It would therefore seem that esters diffuse more easily through the lipid component of the intestinal barrier. The transport of acetyl- and propionyl-L-carnitine at pharmacological doses seems to be linearly and positively correlated with K+ transport but not with Na+ transport.