Cccxxii. Ketogenesis-antiketogenesis. v. Metabolism of Ketone Bodies

ACETOACETIC and f-hydroxybutyric acids are known to undergo two chief metabolic changes, interconversion and oxidative breakdown. The reversibility of the reaction, acetoacetic acid =,-hydroxybutyric acid, was demonstrated in liver brei by Dakin & Wakeman [1910, 1, 2] and in perfused liver by Friedmann & Maase [1910]. Furthermore, the interconversion of these ketoand hydroxy-acids, both in liver and in kidney, was clearly illustrated by the perfusion experiments of Snapper & Grunbaum [1927, 1, 2, 3]. Using slices, Jowett & Quastel [1935] have shown that /3-hydroxybutyric acid is oxidized to acetoacetic acid in tissues other than liver and kidney. Apart from the interconversion Snapper & Grunbaum found a true destruction of "ketone bodies", which was large in kidney but very small in liver. /3-Hydroxybutyric acid was also destroyed in the extremities of the dog and by the tongue muscles of the calf [Snapper & Griinbaum, 1928]. Quastel & Wheatley [1935] studied the breakdown of acetoacetic acid in kidney slices. Acetoacetic acid disappeared under both aerobic and anaerobic conditions; in the former instance only one-quarter to one-third of the change was due to reduction to ,B-hydroxybutyric acid, whereas in the latter reduction was almost quantitative. The distinct nature of the two processes was demonstrated by the action of inhibitors, e.g. malonate.