Octanoate metabolism in the isolated perfused rat liver. II. Comparison with a long chain fatty acid

Liver of fed rats was perfused in vitro with 10 mmoles/litre lactic acid. Supplementary addition of octanoic acid (1.2 mmoles/litre) increased production of ketone bodies. By doubling the quantity of medium chain fatty acid, production of ketone bodies was doubled. Octanoic acid is as ketogenic aspalmitoleic acid if the two fatty acids are compared molecule by molecule. However, C8 : O is more ketogenic that C16: 1 when the comparison is effected on the basis of an identical number of acetyl groups. Octanoic acid increases glucose production by the liver. It was not possible to show the same phenomenon in the presence of palmitoleic acid. During oxidation of fatty acids the beta-hydroxybutyrate/acetoacetate and lactate/pyruvate ratios of the perfusion medium were increased.