Oxidative Pathways of Carbohydrate Metabolism 169 



pathway since the other two pathways are scarcely affected. 

 The lower glycogen synthesis in a high Na+ medium is due to 

 loss of intracellular K+ and replacement by Na+ which has 

 been shown to alter the activation-inactivation mechanism in 

 favour of increased phosphorylase activity (Cahill et al., 



NORMAL 

 GLYCOGEN 



49 0/7% 



co^i 



NORMAL 

 GLYCOGEN 



18' 



25 



G-6-P 



-> CO. 



G-6-P 



(E-M 



pathway) 42 ' 



(pentose P (E-M 

 pathway) pathway) 55 /^ 



GLUCOSE 



High Na+ Medium 



^COj 

 (pentose P 

 pathway) 



GLUCOSE 

 High K+ Medium 



19 



DIABETIC 

 GLYCOGEN 



2 



6' 



^CO, 



(E-M pathway) 



73 



(pentose P pathway) 



GLUCOSE 



High K+ Medium 



Fig. 5. Pathways of G6P metabohsm in rat liver shoes. Data of Ashmore and 



co-workers (1957). 



1957). Glucagon and adrenaline produce a similar effect 

 (Cahill et al., 1957; Berthet, Sutherland and de Duve, 1957). 

 In diabetes the ability to phosphorylate glucose is very 

 greatly reduced and Ashmore and co-workers (1957) found 

 that liver slices only phosphorylated 10 [xmoles glucose per g. 

 liver in 90 minutes in comparison with normal liver slices 

 which phosphorylated about four times this amount. Of the 

 G6P available, a much smaller proportion is used for glycogen 

 synthesis. This is probably related to increased G6Pase 



