Effects of Choline Deficiency and Carnitine on Palmitic Acid Oxidation by Rat Liver Homogenates

Abstract

The conversion of C14 carboxyl-labeled palmitic acid to CO2 and ketones by liver homogenates prepared from choline deficient rats maintained on a 20% protein diet was within the normal range, indicating that hepatic fat oxidation is not impaired in the absence of choline alone. Carnitine addition in vitro augmented ketogenesis by livers from all groups of rats tested, while choline addition in vitro was without effect. Choline administration in vivo resulted in an enhanced oxidation of palmitic acid to CO2 by liver homogenates obtained from choline-deficient animals. However, liver preparations from animals injected in vivo with choline continued to respond to carnitine addition in vitro with an enhanced ketogenesis. It was concluded that carnitine and choline influence different parameters of fat metabolism.