TRIGLYCERIDES AND FATTY ACIDS 121 



ketogenic, while substances which tend to prevent the accumulation of the 

 ketone bodies in the tissues are called antiketogenic by one school, and 

 ketolytic-^- bj^ another group. The difference in terminology refers to the 

 mechanism by which it is believed that these substances prevent the ac- 

 cumulation of ketone bodies. 



It is generally accepted that, under normal conditions, fatty acids are 

 oxidized to CO2 and H2O, thus setting free the maximum amount of energy 

 that is bound up in the molecule. In the course of degradation of the fatty 

 acids, the ketone bodies are intermediates. It has long been the accepted 

 opinion that, in order to complete the oxidation of the fatty acids to CO2 

 and H2O, carbohydrate must be simultaneously oxidized to effect the com- 

 plete breakdo\Mi of the ketone bodies. Naunyn-®^ elaborated the theory of 

 "secondary oxidation," and Rosenfeld-^-* stated, many years ago, that "fats 

 burn only in the flame of carbohydrate." While this aphorism has been 

 somewhat in disrepute in recent years, the fact remains that ketonuria de- 

 velops in the absence of carbohydrates or carbohydrate precursors, while it 

 disappears when such substances are metabolized. The demonstration of 

 the interrelation between the metabolism of ketone bodies and the Krebs 

 cycle has re^dved the acceptance of the Naunyn-Rosenfeld statement. The 

 historical aspects of ketosis were reviewed by Magnus-Levy,-^^ Shaf- 

 fer, -^^ and Stadie,- while the more recent metabolic work has been sum- 

 marized in the papers of MacKay-®^ and of others. One of the best critical 

 reviews to be found is the monograph of Peters and Van Slyke.^^* 



(a) Historical Development. Acetone was the first of the ketone bodies to 

 l)e recognized in biological material. Thus Petters,^®^ in 1857, discovered 

 acetone in the urine of diabetics. He considered it to be an intermediate of 

 glucose. Acetoacetic acid was the second ketone body to be identified. 

 Gerhardt"° described the presence of this compound in diabetic urme eight 

 years after the discovery of acetone. 



262 According to G. Lusk, Elements of the Science of Nutrition, 4th ed., Saunders, 

 Philadelphia, 1928, page 665, the term "ketoh'^tic," in place of "antiketogenic," was 

 introduced at the suggestion of Professor S. R. Benedict. 



2" B. Naunyn, cited by P. A. Shaffer, Medicine, 2, 375-404 (1923). 



2e< G. Rosenfeld, Berl. klin. Wochschr., 43, 978-981 (1906). 



2« A. :Magnus-Levy, Ergeb. inn. Med. u. Kinderheilk., 1, 352-419 (1908). 



2«« P. A. Shaffer, Medicine, 2, 375-404 (1923). 



267 E. M. MacKay, /. Clin. Endocrinol., 3, 101-110 (1943). 



26* J. P. Peters and D. D. Van Slyke, Quantitative Clinical Chemistry, 2nd ed., vol. I, 

 Williams & Wilkins, Baltimore, 1946, pp. 489, 494. 



2^5 W. Petters, Prager Vierteljahresschr. prakt. Heilk; cited by F. Hirschfeld, Z. Klin. 

 Med., 28, 176-209 (1895), p. 176. 



2™ C. Gerhardt, Wien. med. Presse, 6, Xo. 28, 673 (1865); also cited by F. Hirschfeld, 

 Z. klin. Med., 28, 176-209 (1895), p. 176. 



