THE FORMATION IN THE ANIMAL BODY OF I-fl-OXY- BUTYRIC ACID BY THE REDUCTION OF ACETO-ACETIC ACID

It is well known that /3-oxybutyric acid and substances capable of giving rise to this acid may undergo oxidation in the liver with formation of aceto-acetic acid and acetone. This has been most convincingly demonstrated by the striking experiments of Embden and his co-workers upon the perfusion of surviving livers with blood containing P-oxybutyric acid, etc. The reaction involved in this oxidation of ,&oxybutyric acid has been shown by Wakeman and the writer to be due to an oxidizing enzyme whose action was facilitated by the presence of free oxygen and of oxyhemoglobin or b1ood.l One of the main objects of the following paper is to point out the reversible nature of this reaction. If aceto-acetic acid in the form of its sodium salt beinjectedintravenously into cats or dogs, a reduction occurs of a considerable part of the salt with formation of hevo-rotatory ,&oxybutyric acid which is excreted in the urine. Thus the injection of 12 grams of aceto-acetic acid was followed by the elimination of 1 to 2 grams of /3-oxybutyric acid. This fact was recorded in a short paper2 sent on March 16 to the Journal of the American Medical Association, which, however, notwithstanding a promise of prompt publication, did not appear until April 29. In the meantime a paper appeared byBlum3 (March