168 F. Dickens, G. E. Clock and P. McLean 



Table II 



Participation of pentose phosphate and glycolytic pathways in 



glucose catabolism in liver, calculated from experiments 



using specifically labelled glucose 



a Katz et al. (1954). 



b Ashmore et al. (1956). 



c Bloom and Stetten (1955). 



d Wenner and Weinhouse (1956ffl). 



e Murphy and Muntz (1957). 1 



/ Muntz and Murphy (1957). 



recirculated, and in the latter experiments to the fact that 

 they were of only a few seconds' duration so that recycling 

 was reduced to a minimum. 



Although this paper is concerned with oxidative pathways 

 of glucose metabolism, it is important to realize that they 

 account for only a part, and under certain conditions for only 

 a small part, of the total G6P metaboUzed by liver. In this 

 connexion, the recent work of Hastings, Ashmore and associ- 

 ates is of great importance. Employing differentially labelled 

 glucose and uniformly labelled fructose, Ashmore and co- 

 workers (1957) measured the uptake of sugars and their 

 conversion to glucose, glycogen and CO2 in liver slices under 

 different conditions. From these results they calculated the 

 amounts of G6P metabohzed by the four alternative path- 

 ways. Some of their results are summarized in Fig. 5, from 

 which it is obvious that the pattern of metabolism is altered 

 considerably both by changes in cation concentrations of the 

 suspending medium and more profoundly in liver slices from 

 diabetic rats. Glycogen synthesis is much greater in a high 

 K+ medium than in a high Na+ medium. This enhanced 

 glycogen synthesis is mainly at the expense of the E-M 



