Activity of glycogen synthase and phosphorylase and glucose 6-phosphate content in renal clear cell carcinomas

Eleven renal clear cell carcinomas were investigated with regard to their glycogen and glucose 6-phosphate (G6P) content and the activities of glycogen synthase and phosphorylase. Compared to normal cortex from the same kidneys, all tumours revealed increased glycogen and G6P content. The activities of phosphorylase a and b as well as of synthase R and D were also increased. Synthase I activity, however, was reduced. It was concluded that in these tumours glycogen synthesis may preferentially be catalyzed by synthase R which is activated by G6P. These findings agree with those in some other glycogenotic tissues and support the concept that an accumulation of G6P is associated with excessive storage of glycogen in preneoplastic and neoplastic lesions.