Activity of rat liver enzymes responsible for glycogen metabolism after whole-body irradiation.

The activities of liver enzymes involved in the breakdown and synthesis of glycogen have been investigated in rats exposed to 1200 rads midline kerma dose, freein-air, of x rays or mixed gamma-neutron radiation. It was found that glycogen phosphorylase and amylo-1, 6-glucosidase, both of which are involved in the breakdown of glycogen to "glucose" units, are greatly inhibited by both qualities of radiation. A considerable inhibition in the activity of amylo(1,4 ->1, 6)-transglucosidase (branching enzyme) was also observed. In contrast, it was found that the activity of UDP-glucose-glycogen transglucosylase which is responsible for the in vivo synthesis of 1,4-polysaccharides is greatly enhanced when the animal received x rays or mixed gamma-neutron radiation.