MODE OF FORMATION OF FATTY ACIDS FROM 

 ACETATE AND GLUCOSE AS STUDIED IN THE 



MAMMARY GLAND 



G. POPJAK 



Soon after the introduction of deuterium as a tracer 

 element by Schoenheimer and Rittenberg (1935), it was 

 discovered that when the body water of animals is enriched 

 with DgO, the fatty acids, among other body constituents, 

 become labelled with deuterium. Schoenheimer and Ritten- 

 berg found that when the animals were given DgO to drink 

 for many days the concentration of D in the fatty acids reached 

 about 50 per cent of that in the body water. They adduced 

 convincing proof that the incorporation of the isotope into 

 fatty acids in stably bound form was due to the synthesis of 

 the acids in the body, and with remarkable intuition they also 

 inferred that in this synthesis small molecules must have been 

 involved (see Schoenheimer, 1941). A few years later Bloch 

 and Rittenberg (1942a, h) made the further important 

 discovery that the small molecules from which fatty acids 

 and cholesterol are synthesized are acetate units or some more 

 reactive derivatives of acetate. The precise mode of the 

 condensation of these Cg units to form the long-chain fatty 

 acids and the nature of the intermediate compounds have, 

 however, eluded discovery to a large extent. 



Recently I have been fortunate in having been associated 

 with some work on the metabolism of the mammary gland, 

 the results of which seem to offer at least a partial solution of 

 this problem. The work to be described was done in collabo- 

 ration with a number of colleagues. Dr. S. J. Folley and Dr. 

 T. H. French of the National Institute for Research in 

 Dairying, L^niversity of Reading, and Dr. G. D. Hunter and 



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