Polyglucose particles histochemically synthesized by glycogen synthetase activity in the living chick retina

Electron histochemical techniques for glycogen synthetase has been applied to the living retina of the chick and the polyglucose particles synthesized from UDPG in the paraboloid of the accessory cone were compared with those synthesized by the conventional histochemical techniques. In the retina incubated in the medium for glycogen synthetase in vivo, synthesized polyglucose particles were located in the cytoplasmic matrices and most of the particles were less than 200 A in diameter. These particles were rather well stainable with lead citrate and filled the cytoplasmic matrices. However, the tubular structures were not flattened, but slightly dilated. Compared with polyglucose particles synthesized in vitro by glycogen synthetase, those demonstrated by the in vivo histochemical techniques showed closer resemblance to native glycogen particles in size and stainability with lead citrate. The polyglucose particles synthesized from UDPG by glycogen synthetase were apparently different from those synthesized from glucose-1-phosphate by phosphorylase and branching glycosyltransferase.