Glycogen in endothelial cells

Polyglucose newly synthesized by phosphorylase in endothelial cells of rabbit aorta was studied electron microscopically by Takeuchi and Sasaki's method to confirm the presence of phosphorylase activity in endothelial cells of aortic wall. The polyglucose stained irregularly with lead, forming irregular particles 200–500 A in diameter. It was found in both endothelial cells and smooth muscle of the aorta. Native glycogen was not recognized in endothelial cells, but was present in the smooth muscle of the media. On the contrary, both polyglucose and native glycogen were observed in the intermyofibrillar sarcoplasm of heart muscle, which was simultaneously studied as a control.