PAT METABOLISM 



Thai higher fatty acids, Buch as caproic 0,H 0, and caprylic C,H « >_ . bi 

 actually been isolated from the products of ti entation is a •■ 



and it is of interest to note thai L< and an 



acids ■ sur during the aseptic ii d of liver pulp ' . the 



increase of fatty acid could not be Bhown to be affected by addii _ the 



liver which, according to the above equal id. 



The Method by Which the Fatty Acid is Broken Down, [n tl mi- 



ca! laboratory, ordinary oxidizing agents attack tl e fatty-acid chain ;it the 

 C-atom iir\t the carboxy] (COOH group (the alpha C-atom). B I 

 this can nol occur in the animal body, because it would leave behind a 

 smaller chain containing an uneven number of C-atoms, and such chains 

 are never found presenl in the animal fats. < >n the contrary, the com- 

 moner fats all contain an even number of < ' atoms thus : Butyric, C I ! 

 palmitic, C II 2 ; stearic, C II 2 ; oleic, C 1 1 



The intermediary substances which are produced during the gradual 

 breakdown of the fatty-acid molecule in the normal animal are of a v< 

 transitory character so much so indeed that it is impossible for any one 

 of them to accumulate in sufficient amounl to permil of isolation, or even 

 detection, by chemical means How then are we to idi 



mediary products? This has 1 o rendered possible by the discovery that, 



when anything occurs to disturb tlie normal course of fat metabolism, as, 

 for example, when the tissues are deprived of carbohydr; as in star- 



vation or in severe diabetes . the oxidation of the fatty-acid chain stops 

 short when ;i chain of four C-atoms still remains unbroken. Those 

 four ( '-atoms seem to form a residue thai is more resistant to oxidation 

 than the remainder of the fatty acid molecule. It is a residue, theref 

 which is quite readily further oxidized to CO a and II <> under normal con- 

 ditions, but which, although incapable of becoming completely oxidi 

 when the metabolism is upset, docs undergo a partial oxidation, result- 

 ing in the production of various intermediary products. These accumu- 

 late in the body in sufficienl amounl to overflow into the urine, 

 which they can be isolated and identified. 



The fatty acid with 4 C-atoma is butyric, CH CB 'II COOH, and I 

 firsl oxidation producl formed from it in the body seems to be I 



d, CH CHOHCH COOH. This then 1 omes oxidized t< i a 



body having the formula ''II COCH COOH, d, which, 



further oxidation, readily yields CH COCH . or Tl ib- 



Btanci f-oxybutyric acid, acetoacetic acid and acetone ■at - in the 



urine during carbohydrate starvation, as in diabei 



It mighl be objected, however, thai a chemical pr< ng undi 



abnormal conditions n I not als.. occur in the uiimal. Thai it 



probablv docs, however, is indicated h\ the result incuts 



