Formation of Fatty Acids 



279 



of an energy producing nature than a specific action in making available 

 some particular compound. 



In Table I there are some figures obtained with liver slices from normal 

 rats, with and without insulin. We have used both carboxyl labelled 

 acetate and methyl labelled acetate. These were controlled experi- 

 ments in which slices from the same liver were used in each pair. It 



Table I 



Conversion of Carboxyl or Methyl Labelled Acetate to Fatty Acids 

 AND THE Effect of Insulin upon this Process 



is seen that in every case there is a marked increase in the incorporation 

 of ^*C into the fatty acids. In the last column we have calculated the 

 number of micromols of substrate incorporated per standard amount of 

 fatty acid. 



I will now discuss briefly the results obtained with liver slices from 

 normal and diabetic rats (Table II). I wish to draw your attention to 

 the last column which gives the micromols of substrate incorporated 

 per standard amount of recovered fat. There is again an insulin effect 

 but I do not wish to discuss that for the moment. I want, incidentally, 

 to point out that the short chain fatty acids, butyric, hexanoic and 

 octanoic, are well utilized for the synthesis of long chain fatty acids. 

 This fits in quite well, I think, with some of the concepts Dr. Popjak 

 has discussed. If we examine a series of livers from rats treated with 

 alloxan, it is seen that the number of micromols of acetate taken up is 

 drastically reduced. The incorporation of i*C from the short chain 



