Variations of glycogen level and alpha-glucosidase activity in human malignant epithelial cell lines in culture.

1. Acid lysosomal and neutral alpha-glucosidase activities are measured during the culture of five human malignant epithelial cell lines, as a function of the growth-related glycogen accumulation. 2. Neutral alpha-glucosidase is found to be active mainly during the exponential phase of cell culture, which could be related to an enhancement of glycosylated compound synthesis. 3. The latent activity of the acid lysosomal alpha-glucosidase increases during the course of cell culture and especially when glycogen accumulates, suggesting that this enzyme could be involved in the control of the polysaccharide storage within the cell.