A comparison of the oxidation of octanoate-1-C14, -7-C14, and butyrate-1-C14 by neoplastic and normal mouse tissues.

The degradation of fatty acids of the even series by animal tissues yields Ca fragments (metabolically, acetyl-S-CoA) which may undergo various condensation reactions. Condensation with oxalacetate to form citrate is the established mecha nism for entrance of €2fragments into the tricarboxylic acid cycle, where they are subsequently oxidized to COs (11, 17). Liver possesses the abil ity to form large amounts of acetoacetic acid (AcAcOH) from C2 fragments (12, 14, 15, 22); other tissues, such as kidney (8), also form this ketone body to a lesser degree. Medes et al. (16) first showed, with rat liver slices, that the (C— C)2,i carbon-pair1 of butyrate was asymmetrical ly distributed between the CH3CO — and -CHsCOOH moieties of AcAcOH. According to Crandall et al. (5, 6, 10), the nature of the asym metry depends upon the position of the carbonpair in the fatty acid. These workers observed a C*O:C*OOH ratio2 of about 3.3 in the AcAcOH formed from octanoate-7-C14 by rat liver homogenates, and a ratio of about 0.7 from octanoate-1C14. It is now recognized that the C*O:C*OOH